Date   

Nik Sharpener (was:Scanner Training Advice)

effzee@...
 

From: samarsh@...
Subject: Re: Scanner Training Advice (was: UCR vs GCR...or Neither - RAW CMYK?)

Each time you check a new area of the image, its a new 'max
detail' scan. This can take about 30 seconds just to evaluate the
USM.

Dan wrote to me that Photoshop is better. Now I understand
what he meant.

No matter how many options, or how good the tool - if it is hard
or impractical to use, the results may be poorer than
Photoshops 'poor' USM.
I was wondering if anyone here has used and has an opinion on Nik Sharpener Pro.
We've been using it a while now because we we're getting huge variations from
user to user in sharpening and some customers had complained. Now, we're all
pretty much in the same ballpark and are getting some superb results, really. The only
caveat seems to be a shift to yellow in neutral areas, but I cure that but fading
to luminosity.

Any reason not to be using it? It cost enough...

W. Garabrant
Kulmbach, Germany


Re: Why is this (noisy k plate)?

Hector Davila
 

http://home.netcom.com/~amerphoto/TinType/
http://home.netcom.com/~amerphoto/TinType/tintype.html

The third photo I deleted the CMYK Black channel.
Tintype-3.JPG

samarsh@... wrote:


--- In colortheory@y..., APR <amerphoto@i...> wrote:
Why is this?

I'm just expermenting.
APR, this is where most 'breakthroughs' are made. <g>

I take an old Tin Type photo.
Can you explain? Film or print? Colour or g/scale? An old tin type
photo means nothing to me.

I then adjusted in Lab for contrast.
Have you tried an adjustment layer set to luminosity, or a regular
curve with the fade to luminosity command,or duping the layer
curving then blending in luminosity mode or etc...

I then change to CMYK and
I deleted the Black channel
(since I see a lot of scratches and spots in Black channel)
Usually nose and jpeg artifact reduction/removal is attempted in
the AB channels of LAB, or in RGB/CMYK in a duped layer set to
color blend mode. I like to combine both methods, so the
luminosity of the original is not altered, only colour.

These changes then 'migrate' into the RGB or CMYK channels,
providing cleaner noise reduction than direct removal of noise.

...and all of a sudden 90 percent of scratches and spots are
gone.
It even looks sharper than the original without sharping it.
Also, I see more detail.
I would expect this to be the case for the B or Y channels - not the
K as such...but the CMY inks can really hide artifacts in the K
channel (with a light black GCR or UCR sep). This does not
excuse a messy plate - but the K is a bit different to others.

It would REALLY depend on the image and output.

How is the CMYK conversion performed? What type of built in
setting or profile is in use? What settings, such as BPC etc.


So, why is that?
Why are the scrathces and spots gone?
Why is it more sharper and has more detail.
What is it about removing the black channel that
causes this?
Can you post the original on the web, or email it off list to me?

I then go to Greyscale mode and back to LAB and CMYK curves
to bring back the contrast and blacks.
I personally would not do this in production, but I understand that
you are playing.

I just want to know, what is the Black channel all about?
Basically, CMY do not make a nice solid rich black, but a redish
muddy dark brown. The K black plate adds definition or Key.
There are many ways to produce black, being dependent on
output and image content. The K plate is you biggest enemy and
ally when it comes to four colour print.

Hope this helps,

Stephen Marsh.


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Re: Why is this (noisy k plate)?

samarsh@...
 

--- In colortheory@y..., APR <amerphoto@i...> wrote:
Why is this?

I'm just expermenting.
APR, this is where most 'breakthroughs' are made. <g>

I take an old Tin Type photo.
Can you explain? Film or print? Colour or g/scale? An old tin type
photo means nothing to me.

I then adjusted in Lab for contrast.
Have you tried an adjustment layer set to luminosity, or a regular
curve with the fade to luminosity command,or duping the layer
curving then blending in luminosity mode or etc...

I then change to CMYK and
I deleted the Black channel
(since I see a lot of scratches and spots in Black channel)
Usually nose and jpeg artifact reduction/removal is attempted in
the AB channels of LAB, or in RGB/CMYK in a duped layer set to
color blend mode. I like to combine both methods, so the
luminosity of the original is not altered, only colour.

These changes then 'migrate' into the RGB or CMYK channels,
providing cleaner noise reduction than direct removal of noise.

...and all of a sudden 90 percent of scratches and spots are
gone.
It even looks sharper than the original without sharping it.
Also, I see more detail.
I would expect this to be the case for the B or Y channels - not the
K as such...but the CMY inks can really hide artifacts in the K
channel (with a light black GCR or UCR sep). This does not
excuse a messy plate - but the K is a bit different to others.

It would REALLY depend on the image and output.

How is the CMYK conversion performed? What type of built in
setting or profile is in use? What settings, such as BPC etc.


So, why is that?
Why are the scrathces and spots gone?
Why is it more sharper and has more detail.
What is it about removing the black channel that
causes this?
Can you post the original on the web, or email it off list to me?

I then go to Greyscale mode and back to LAB and CMYK curves
to bring back the contrast and blacks.
I personally would not do this in production, but I understand that
you are playing.

I just want to know, what is the Black channel all about?
Basically, CMY do not make a nice solid rich black, but a redish
muddy dark brown. The K black plate adds definition or Key.
There are many ways to produce black, being dependent on
output and image content. The K plate is you biggest enemy and
ally when it comes to four colour print.

Hope this helps,

Stephen Marsh.


Re: Scanning Class information??

Chris Brown <cb@...>
 

Re. Scanning Class:

I have been seeking out a scanner operator class with no luck (all
that I found are on-site and product-specific classes). I did find one in
the UK but being on the west coast, that's a little further than I care to
travel. I have not seen any such course offered by Sterling-Ledet but am
assuming such information is available to them. I'm hoping for a more
general (if possible) class, and since I am not currently working,
"on-site" is not an option. Hopefully with a class of this type added to my
resume the dry market might dampen up.

Anyway, noticing a new thread in the discussion group as well as your
standing in the education field, I thought I might inquire as to your
knowledge of the availability of any such courses. Any information and/or
recommendations of such courses would be appreciated.
Try posting your questions and queries on ScanHi-End@...

Although the discussions can get equipment-specific, I have found answers to
most of my film scanning questions, from oil mountnig film on a drum to
mapping RGB values to a specific output targets. There are even several
software and hardware representatives who read and post on a regular basis.

As for the whole UCR, GCR, UCA discussion, it really helps to talk to actual
press operators. The bigger the press and volume of the printing company,
the better. These people really know why an image might print poorly or
perfectly, if it has too much overall ink, or the sep is (color) biased in
some way, etc.

Chris
@
Chris Brown Photography
http://www.chrisbrownphoto.com
Vox: (217) 356-0540 * Fax: (217) 356-1394


Re: Smooth Skin?

Gordon Pritchard <gordon_pritchard@...>
 

RE: APR wrote:

Thanks everyone for the "Smooth SKin" techniques, I'm now an expert!
==========================

One item that I did not see covered in the thread is the impact of halftone
screening on smooth tones. You may want to investigate round dot (round dots
simply grow larger from highlight to shadow) or even FM screening (esp if
presswork is from CTP). Halftone have an "optical bump" when the dots first
touch in the tone scale. With Euclidean (round - square - round) this
happens at the 50% dot. With elliptical it's split between 40 and 60%. Both
screens have the bump in critical tone areas. Round dot places the optical
bump at 75%. Well into the shadows where it is much less visible. Some
printers also try to use exotic screening strategies to avoid rosettes,
which can also appear as "noisy" tones in critical skin color areas.

thx, gordo


Gordon Pritchard
Commercial Print Specialist
CreoScitex
Vancouver Canada
T: 604.451.2700 ext 2870
C: 604.351.2437
gordon_pritchard@...
http://www.creoscitex.com

Print - dot's what it's about!<


Re: Smooth Skin?

Hector Davila
 

Thanks everyone for the "Smooth SKin" techniques, I'm now an expert!


Why is this?

Hector Davila
 

Why is this?

I'm just expermenting.
I take an old Tin Type photo.
I then adjusted in Lab for contrast.
I then change to CMYK and
I deleted the Black channel
(since I see a lot of scratches and spots in Black channel)
...and all of a sudden 90 percent of scratches and spots are gone.
It even looks sharper than the original without sharping it.
Also, I see more detail.

So, why is that?
Why are the scrathces and spots gone?
Why is it more sharper and has more detail.
What is it about removing the black channel that
causes this?

I then go to Greyscale mode and back to LAB and CMYK curves
to bring back the contrast and blacks.

I just want to know, what is the Black channel all about?
Am I doing something right or wrong?


Thanks,
Hector Davila


Re: Scanner Training Advice

samarsh@...
 

Martin replies:

Sorry, I didn't make myself very clear on this point.

The light source on the flatbeds is extremely critical when it
comes to the
apparent sharpness of the images. IMO the first Scitex and
Scanview flatbeds
produced horrible, oversharpened images. The results from
photographic
prints were pretty much unusable unless the USM was turned
off!

The smallest specs of dust or surface imperfections were
magnified, so your
high quality fibre print ended up looking a real mess.

Scanview have since modified the light source to make it less
focused and
more diffuse -- this cured the problem.
I don't think that things have changed, even on the top of the line
model purchased less than six months ago...

The main pre press guy who does most of the scanning comes
from a traditional background - USM in the scan.

As you and many others have noted, the EverSmart line have a
very crisp 'print' look - even with USM off. I have to agree.
Photographers who output to Lightjets or other contone devices
do not like this effect, and are quite vocal on it.

For transmissive scans, this seems an advantage - but I am
biased towards commercial flatsheet offset.

For transmissive, scaner USM may be OK, but if left to my own
devices I would sharpen reflective prints in Photoshop.

Reflective photo prints really suffer from the USM, they look
crunchy on the monitor - but it's amazing what an equalizer the
halftone screen is - even at 175 lpi using CTP.

The USM control in the scanner does have a good grain control,
plus there is also optical defocusing and then the red, green or
red/green filter combo in the scanner...

I think I will really have to pick the CreoScitex guys brain on the
extended USM functions.


Each time you check a new area of the image, its a new 'max
detail' scan. This can take about 30 seconds just to evaluate
the
USM.
This is similar to our scanner -- we get a general preview that
is fairly
mediocre -- but can choose to scan a portion at final resolution
before
committing the whole image.

Unfortunately you just have to keep a bunch of settings in your
mind --
ColorQuartet allows adjustment of strength, noise, light
contours, dark
contours and contour thresholds. With power comes the
responsibility to
RTFM!
Too true. Thats why it's so easy for many to stick to factory
defaults.

There is a weird table called 'LUT.id' which I cant find any
mention of - but I presume it is something to do with
calibration.

Lut is a look-up-table which is probably used to display your
image on
screen, or convert native Lab data to RGB.
I am familiar with LUT's, as this is our default method for
acquiring CMYK (or perhaps one day the odd RGB) scans.

What I mean is that you can choose two colour modes for the
scan. CMYK or perhaps RGB.

Then there are two real options for scanning into a specific
space or flavour, with a third option being the device link section.

The first option, is the input/output ICC profiles. You can scan
from ref/trans scanner RGB input to other output modes, or raw
scanner space (with or without a tag). This is all ICC driven.

The second option is to use the default RGB or CMYK table
option for separation or colour description. The input is the
default ref/trans RGB input description. This is the old style
format, proprietary CLUT approach. It is also used for the non
ICC Scitex monitor calibration/colour matching tool - since these
tables are out of the ICC softproofing link.

This 'table' section has the second option with the lable 'LUT.id'.

I recall reading somewhere online, but cant find where - that this
is used in ICC scanning or something...either IT8 scanning or
perhaps raw untoned high bit editing.

Either way, it probably is not a concern for us.

This LUT.id provides a very flat, untoned image. But I guess it
has a use - I can sleep till I find out on the training day.


There are also 'device link profiles' which are a proprietary
combination of tables/profiles/scanner settings which are
presaved into a 'profile'.

This does not seem to be a true ICC profile - but a proprietary
one.
Proprietory always bothers me -- which is why we don't buy
much Scitex kit.
This is true, up to a point - but I think times are changing.
Perhpas the Lino approach is giving them some competition.

The eversmart uses LS or luminance/saturation curves - but LAB
is not an option that I know of - even with ICC profiles. I dont have
a LAB ICC profile, only an old Kodak CM 'precision transform' file
which does not show up. So they are not directly going after the
Lino method of using LCH editing.

The proprietary issue for me is the default CMYK table - which is
fantastic for most work. This gives much better colour than the
ICC options - but not detail in some cases.

It is my guess that this is a gamut compression issue - or lack of
it. The default tables we like would use relcol rendering, so this
probably accounts for the lack of detail in some tough originals.

We rarely (never) scan in ICC mode, or as RGB and convert in
Photoshop - which does have certain benefits for certain
images.

The 'Device Link Profiles' in question are proprietary - but only in
the sense that they are a scanner preset.

You can choose default tables or ICC methods describing your
RGB or CMYK scans - the device link profile is just a package for
holding these proprietary or ICC settings along with scanner
functions such as endpoints, gradation, USM etc.

The problem is that some of this is ICC, some is scanner
specific - all bundled up in a proprietary file. The confusion in my
mind is the word 'profile' - not all profiles are ICC profiles.
CreoScitex use the term, which creates confusion since the only
other option for defining RGB or CMYK is through ICC profiles,
with or wthout the use of these specific scanner settings.

One thing that I find amusing is how beauty is in the eye of the
beholder. I have read comments from noted ICC proponents on
other lists that they would not use the CreoScitex gear because
of how poorly it handles CM (or used to).

My problems are more petty.

If you do a full bed preview of many originals - before making
your various crops/scans you can only set the crops at this
postage size preview.

After you do an aptly named 'crop preview' - there is no way to
fine tune the crop, which must be done in Photoshop.

This way you are forced to overshoot, so that critical edge content
is not missed. But this is a workflow issue, the scanner is
designed for premounting of originals on registration pin
punched sheets - and the scanner automatically scans and
crops out the pre configured mask window positions.

If you do not have the image rotated correctly - there is no way to
do this in scanner software, only mirroring. You have to rotate the
image in Photoshop.

The prosumer Umax MagicScan software that I used to use did
all this and more. At least software can be upgraded, if
CreoScitex ever get a clue.

And one final observation which really amuses me - and is
probably why some pundits hate the scanner/software:

There is no histogram display (sorry to mention the H word Dan)
<g>

I find the Leaf approach of mapping a simple three point curve
over a histogram interesting...it would make some levels users
more comfortable using curves.

The EverSmart softwares curve control has a nice feature which
is on my wish list for Photoshop - a diagonal reference line is
always dispayed.

This lets you quickly visually judge exactly how steep the curve is
in relation to neutral, as well as bringing the curve back to true in
the midtones and shadows, while you tweak the quartertones
(for example). Such a simple visual aid is very, very nice - and
seems obvious for Photoshop in hindsight.

Sincerely,

Stephen Marsh.


Re: Scanner Training Advice (was: UCR vs GCR...or Neither - RAW CMYK?)

Martin Orpen <orpy@...>
 

on 9/10/01 1:39 pm, samarsh@... at samarsh@... wrote:

4. Black and white prints. Take one of these along as a test of
the
scanner's light source.
Are you referring to native scanner RGB grey balance?
Sorry, I didn't make myself very clear on this point.

The light source on the flatbeds is extremely critical when it comes to the
apparent sharpness of the images. IMO the first Scitex and Scanview flatbeds
produced horrible, oversharpened images. The results from photographic
prints were pretty much unusable unless the USM was turned off!

The smallest specs of dust or surface imperfections were magnified, so your
high quality fibre print ended up looking a real mess.

Scanview have since modified the light source to make it less focused and
more diffuse -- this cured the problem.


Each time you check a new area of the image, its a new 'max
detail' scan. This can take about 30 seconds just to evaluate the
USM.
This is similar to our scanner -- we get a general preview that is fairly
mediocre -- but can choose to scan a portion at final resolution before
committing the whole image.

Unfortunately you just have to keep a bunch of settings in your mind --
ColorQuartet allows adjustment of strength, noise, light contours, dark
contours and contour thresholds. With power comes the responsibility to
RTFM!

There is a weird table called 'LUT.id' which I cant find any
mention of - but I presume it is something to do with calibration.
Lut is a look-up-table which is probably used to display your image on
screen, or convert native Lab data to RGB.


There are also 'device link profiles' which are a proprietary
combination of tables/profiles/scanner settings which are
presaved into a 'profile'.

This does not seem to be a true ICC profile - but a proprietary
one.
Proprietory always bothers me -- which is why we don't buy much Scitex kit.

--
Martin
Idea Digital Imaging Ltd - the "image" specialists
http://www.idea-digital.com


Scanner Training Advice (was: UCR vs GCR...or Neither - RAW CMYK?)

Dan Margulis <76270.1033@...>
 

Stephen writes,

I was wondering if you and perhaps the list have any thoughts on
how I could maximise the training. I know many on this list attend
specific training or seminars - are there any tips from all those
people who have 'been there - done that'.>>

As one who's been to a *lot* of scanner training, let me suggest that
everything depends on the instructor. They range in my experience from
highly qualified and insightful to total baboons. It's well worth your
while to insist on speaking to the instructor in advance to find out what
kind of person you can expect. Often you'll find that the individual has
certain experience that you can really mine. If the person has been a
professional scanner operator, plan on spending a lot of time discussing
techniques for specific originals, but don't expect more than a book
recitation of what the conversion software does. Similarly if the person is
a software geek you may be able to go in depth in that area. And if your
impression is that the instructor is as dumb as a sack of rocks, just go
with a fixed itinerary of things you need to see and hope for the best.

Also: re the forwarded question about open-to-the-public scanner training:
I'm not aware of that kind of training being available anywhere, but that
doesn't mean it doesn't exist.

Dan Margulis


Re: Scanning Class information??

samarsh@...
 

I have been seeking out a scanner operator class with no
luck (all
that I found are on-site and product-specific classes). I did find
one in
the UK but being on the west coast, that's a little further than I
care to
travel. I have not seen any such course offered by
Sterling-Ledet but am
assuming such information is available to them. I'm hoping for
a more
general (if possible) class, and since I am not currently
working,
"on-site" is not an option. Hopefully with a class of this type
added to my
resume the dry market might dampen up.
If you have attended one of Dan's colour correction workshops -
then I presume that you are at a certain level of experience in pre
press or photography etc. One would not presume that you are
rank amateur (unless you had generous employers or some
spare money to throw around).

This should be a good thing to note on the resume.

Now I guess that you are not referring to traditional horizontal
PMT drum scanning.

In Australia, graphic repro apprentices specialised in this field
and learned the craft over a four year period - from experienced
and knowledgeable tradespersons.

If you are talking of high to medium end flatbed scanning, then
this would not require the same sort of background.

There is not much in the hardware side to learn. Cleaning
originals is not rocket science. Mounting originals is usually very
straight forward as well. Some flatbeds have oil mounts, and I
have heard of some custom hacks as well - but this is not the
norm for most flatbed users. Oil/gel mounting is messy and
requires more time and work, but the results are probably worth
it...when I think of how much spotting time this removes - not to
mention much better transmissive scans.

What is left is learning the controls of the scanners software and
how they apply to various originals etc - and how to edit by the
numbers or visually with ICC or other methods.

So without devaluating the whole art of scanning too much - if
you are proficient with Photoshop, RGB, LAB and CMYK editing
and have broad production experience in print or imaging etc,
then most of the learning curve is probably covered.

It would depend on the setting you were aiming for...

A traditional by the numbers scanner operator whose main
concern is CMYK and print is one type user employers are after.

An ICC fluent operator who knows RGB and colour management
and scans raw, flat untoned high bit images for high bit editing in
Photoshop for archival is another position.

Even though both are scanner operators - they have very different
outlooks and experience. This is not to say that they are mutually
exclusive.

Since clients do their own scans these days - professional
scanning is more a side issue, for most shops.

As you rightly state - another skill can be a big asset to your
employability.

If my hunch is right about your experience, you are probably most
of the way there now - even if you have not used a scanner.

I can supply some links off list if you would like, which may be of
help.

Regards,

Stephen Marsh.


Re: Scanner Training Advice (was: UCR vs GCR...or Neither - RAW CMYK?)

samarsh@...
 

I originally wrote:

I was wondering if you and perhaps the list have any
thoughts on
how I could maximise the training. I know many on this list
attend
specific training or seminars - are there any tips from all
those
people who have 'been there - done that'.
Martin replies:

I have no experience of CreoScitex training (apart from
LeafCapture on the
Volare camera). However, I have been to a number of scanner
demos and would
offer the following advice:
Thanks for the reply Martin. So, did the LEAF training simply take
you through the printed exercise book, using the half dozen or so
examples or whatever?

I have a gut feeling that my training will not be too extreme.


Take your own originals rather than allowing the
demonstrators to use their
own standard demonstration images. This will enable you to
see how the
demonstrator copes with an image from scratch rather than
have them rattle
through a set routine that they have no doubt done hundreds of
times before.
Very good point.

The scanner comes with some exercise originals...

Trannys, negs, colour reflective, BW ref, Halftone print.

I presume that these will be used, in conjunction with the
exercises which I have used in the manual anyway...but I will see
on the day I guess.

Make sure that your originals are tough scanning propositions,
for example:

1. An *arty* image that has no natural looking highlight,
shadow or gray
midtones. One that has been shot using coloured gels with
vibrant RGB
colours. This should demonstrate how well the demonstrator
can cope with
numbers only -- or whether the scanning software has profiles
for standard
film stocks.
Yes this is a good test, and all the supplied scanner exercise
images do have endpoints...


2. A tranny that has had a hard life. See how the demonstrators
cope with
scratched and pitted originals. If the demo is on drum
scanners then oil
mounting will fill in most of the damage. If it's on a flatbed is it
still
possible to oil mount?
The EverSmart Supreme can oil mount - but this is optional.

CreoScitex also offer an optional Photoshop plug to help
automate dust/scratch removal.

But this would be very good to see, since this scanner seems
very unforgiving of originals quality (also the six surfaces in
scanning trans can be a real dust spotting problem).


3. Under- and over-exposed transparencies. Take one of each
and see how the
demonstrator and scanner hardware cope with pulling out
shadow and highlight
detail.
The range of this scanner is very good, not drum but very very
good.


4. Black and white prints. Take one of these along as a test of
the
scanner's light source.
Are you referring to native scanner RGB grey balance?

I did a test using a Kodak Greyscale - and each patch was within
one or two RGB points of each other, all over the scale. This
scanner, with nothing more than a canned profile - is near grey
linear balanced. It is so close to R=G=B - but you expect that for
the insane price tag!


5. A negative. Don't know what CreoScitex's position on
negative is? Most
conventional repro houses refuse to go anywhere near them. If
the software
is able to produce positives from neg, watch the adjustments
that the
demonstrator carries out.
It's a bit like getting a poor RGB, with no profile. Most repro
places would not like to go near these too!

The scanner has various neg tables for filmtype makes/models -
and this may help up to a point, but is not a holy grail (too many
variables for canned profiles).

It is all memory colours.

This is a strength of CMYK by the numbers editing.

I will attempt to push for this, as I have not got around to playing
with the supplied exercise neg yet. I have inverted/removed the
orange mask before using Photoshop - but not in the scanner,
on raw data before the image is finally acquired.


While your originals are being scanned, take a detailed look at
the USM
functions of the scanner software. Scanner USM is usually far
superior to
Photoshop. However, this usually leads to a fairly complicated
interface
that you tend to forget after the demo and switch to "auto" when
you get
back to the shop :-)
The controls for USM are very good, and you can even use filters
in the scan.

The big drawback is that the scanner does not do this on a live
interactive way.

You change the setting, then perform a new hi res prescan of the
selected area.

Each time you check a new area of the image, its a new 'max
detail' scan. This can take about 30 seconds just to evaluate the
USM.

Dan wrote to me that Photoshop is better. Now I understand
what he meant.

No matter how many options, or how good the tool - if it is hard
or impractical to use, the results may be poorer than
Photoshops 'poor' USM.

Likewise, with the separation settings, the scanner
manufacturers usually
tell you that profile x is best for this and profile y for that. Get as
much
information on the profiles as you can. Find out how easy it is
to edit the
CMYK profiles and whether the same profiles can be used in
Photoshop.
It is my guess that the basic CMYK table will be used.

I will PUSH for an explanation of their crazy OFF/UCR/GCR
function.

There is a weird table called 'LUT.id' which I cant find any
mention of - but I presume it is something to do with calibration.

All other files are true ICC profiles for input/output.

There are also 'device link profiles' which are a proprietary
combination of tables/profiles/scanner settings which are
presaved into a 'profile'.

This does not seem to be a true ICC profile - but a proprietary
one.

It is my guess that ICC scanning, RGB output and the tabled
DT/SOOM will be ignored...but again I will shortly see this for
myself.

That should be plenty for one day!
Martin, you have helped me more than you can know - and with
luck others as well. Cheers!

Stephen Marsh.


Re: Scanner Training Advice (was: UCR vs GCR...or Neither - RAW CMYK?)

Martin Orpen <orpy@...>
 

I was wondering if you and perhaps the list have any thoughts on
how I could maximise the training. I know many on this list attend
specific training or seminars - are there any tips from all those
people who have 'been there - done that'.
I have no experience of CreoScitex training (apart from LeafCapture on the
Volare camera). However, I have been to a number of scanner demos and would
offer the following advice:

Take your own originals rather than allowing the demonstrators to use their
own standard demonstration images. This will enable you to see how the
demonstrator copes with an image from scratch rather than have them rattle
through a set routine that they have no doubt done hundreds of times before.

Make sure that your originals are tough scanning propositions, for example:

1. An *arty* image that has no natural looking highlight, shadow or gray
midtones. One that has been shot using coloured gels with vibrant RGB
colours. This should demonstrate how well the demonstrator can cope with
numbers only -- or whether the scanning software has profiles for standard
film stocks.

2. A tranny that has had a hard life. See how the demonstrators cope with
scratched and pitted originals. If the demo is on drum scanners then oil
mounting will fill in most of the damage. If it's on a flatbed is it still
possible to oil mount?

3. Under- and over-exposed transparencies. Take one of each and see how the
demonstrator and scanner hardware cope with pulling out shadow and highlight
detail.

4. Black and white prints. Take one of these along as a test of the
scanner's light source. Some scanners have real problems with dust and
surface imperfections on prints. You can do the scan in 5 minutes, but then
have to spend an hour removing the blemishes.

5. A negative. Don't know what CreoScitex's position on negative is? Most
conventional repro houses refuse to go anywhere near them. If the software
is able to produce positives from neg, watch the adjustments that the
demonstrator carries out.

Large format negatives and positives are also ideal for spotting
deficiencies on CCD scanners. In particular, check for banding artefacts in
blue skies or red sunsets. If you see these, then you know that your scanner
is using Kodak's last generation of 10K CCD chips. The banding is caused by
connecting wires which run beneath the red and blue colour filters. Kodak
recently redesigned their CCDs -- but most scanner manufacturers are still
using stockpiles of the older model.


While your originals are being scanned, take a detailed look at the USM
functions of the scanner software. Scanner USM is usually far superior to
Photoshop. However, this usually leads to a fairly complicated interface
that you tend to forget after the demo and switch to "auto" when you get
back to the shop :-)

Likewise, with the separation settings, the scanner manufacturers usually
tell you that profile x is best for this and profile y for that. Get as much
information on the profiles as you can. Find out how easy it is to edit the
CMYK profiles and whether the same profiles can be used in Photoshop.

That should be plenty for one day!

--
Martin
Idea Digital Imaging Ltd - the "image" specialists
http://www.idea-digital.com


Smooth Skin?

Dan Margulis <76270.1033@...>
 

Hector Davila writes,

What's the best way to smooth skin on photos?
I've seen *those* web sites where the girls skin looks real smooth.
How do you do that? Is it bluring AB channels?>>

A method that I illustrated at Seybold is similar to the ones mentioned
previously by Lee Varis and John Opitz, but I think is a little better in
avoiding the overly airbrushed look.

1) Make four identical layers. Layer 1 remains untouched.

2) On Layer 2, Gaussian blur, Radius 2.0 (for starters, may adjust).

3) Having blurred Layer 2, apply a curve that lightens the midtone very
slightly.

4) Change layering mode on Layer 2 to Darken. This will disallow most of
the layer because of Step 3, and will only fill in small white blotches.

5) On Layer 3, apply Gaussian blur at double the radius of Step 2. (Reason:
darker spots on the skin tend to be larger than white spots).

6) Having blurred Layer 3, apply a curve that darkens the midtone very
slightly.

7) Change layering mode on Layer three to Lighten. This will disallow most
of the layer because of Step 6, and will only correct age spots and other
dark blemishes.

8) Compare Layer 3 to Layer 4 (an untouched original) and merge the two as
desired with a layer mask.

This, incidentally, is how one "unsharpens" a picture, when a client has
been so helpful as to supply something that's been oversharpened, without
giving us access to the original.

Dan Margulis


Scanning Class information??

Dan Margulis <76270.1033@...>
 

This individual has previously taken my ACT course.

Dan Margulis

--------------- Forwarded Message ---------------

To: Dan Margulis, 76270,1033
Date: Mon, Oct 8, 2001, 3:24 PM

RE: Class information

Dear Dan,

Although I have been following all threads with interest, I don't
think this note would be of interest to the discussion group. Having never
posted anything anywhere online before (just shy I guess) I am working on
the assumption that this question is too specific for the group.

I have been seeking out a scanner operator class with no luck (all
that I found are on-site and product-specific classes). I did find one in
the UK but being on the west coast, that's a little further than I care to
travel. I have not seen any such course offered by Sterling-Ledet but am
assuming such information is available to them. I'm hoping for a more
general (if possible) class, and since I am not currently working,
"on-site" is not an option. Hopefully with a class of this type added to my
resume the dry market might dampen up.

Anyway, noticing a new thread in the discussion group as well as your
standing in the education field, I thought I might inquire as to your
knowledge of the availability of any such courses. Any information and/or
recommendations of such courses would be appreciated.

Regards,


Re: UCR vs GCR...or Neither - RAW CMYK?

Dan Margulis <76270.1033@...>
 

Dave Badger writes,

I have been using Photoshop's Medium Generation for a long time now
because
GCR is supposed to give you better saturation and depth in the darker
colors. I believe this to be true and think that, for example, cyan in reds
being replaced partially by black is a good thing.>>

I would think the opposite would be true. In principle the two results
should be the same. In practice, black is much stronger than cyan is, so
any variance in inking would create a color issue, especially since the
dominant magenta and yellow in the reds will have been reduced to
accommodate the black.

Using this setting means the black is more critical on press, so I would
think using UCR or Light GCR would be better for newsprint since their
black
plate would be less controlled or more dot gain.>>

Certainly inking generally is less in control in newspaper printing.
However, 1) the black ink used on newsprint isn't as powerful as in
commercial printing, therefore the impact of a density change isn't as
severe; 2) in commercial printing, if the black runs too heavily one of the
principal suspects always is that the pressman was attempting to compensate
for small type or type that is difficult to print because of thinness in
part of the strokes, such as Bodoni, Baskerville, or to a lesser extent,
Times Roman. Newspapers generally aren't subject to this effect because
their text face is invariably something like Excelsior or Ionic or Times
Europa that is specifically designed for legibility at the expense of
aesthetics.

So, while I'd agree with the general policy of using a skeleton black in
newspapers, I think there's more of a case for using a heavier black than
there is in other forms of offset.

This statement seems to indicate that people who use Photoshop's Medium
GCR setting are unsophisticated users. Yet you've said one form of UCR/GCR
is not necessarily better then another.>>

Those experienced in preparing images for CMYK, especially if the target is
a press, by and large certainly favor a lighter black than the Photoshop
default. One form of black generation isn't necessarily better, except in
an image-by-image context, and except in the context of how variable one
expectst the output device to be. A lot of the reasons for preferring a
lighter black vanish if the output is going to be inkjet rather than press.

Can you further explain why you favor a skeleton black and are there any
other downsides to GCR then those you listed above?>>

In addition to the issues mentioned earlier, the services of our friends in
the color management community become more important if you're using a
heavier black. Photoshop makes the wrong assumption that black has the same
dot gain as the other inks, whereas in real life it's usually higher. But
it's very much case by case, so a lot of users have incorrect black dot
gain values unless they've really gone to a lot of effort.

If you are using a skeleton black and your black dot gain value is too low,
this isn't great but it isn't a tragedy. If you're using a heavier black
that affects colored areas, you're really risking a muddy sep.

Dan Margulis


Re: Smooth Skin?

Lee Varis
 

APR wrote:

What's the best way to smooth skin on photos?
I've seen *those* web sites where the girls skin looks real smooth.
How do you do that? Is it bluring AB channels?
There are many ways to smooth out complexions but if there are real
physical skin features (not just noise) that need to be smoothed then
blurring the AB channels is not going to do it. One of my favorite
techniques is to make a duplicate layer and run the median or dust and
scratches filter on the new layer with enough of a radius to smooth out
any defects. Option-click on the layer mask icon at the bottom of the
layers pallet to create a black layer mask thus hiding the newly blurred
layer completely. Now you can paint into the layer mask with white using
a soft airbrush, smoothing just those areas that require it.

You'll probably need to add some noise to the blur layer to match the
underlying layer - a small amount in the blur image should be enough to
kill any banding artifacts from the median filter as well. If you have
areas of skin highlights that approach white you might want to add the
noise in an overlay layer. Create a new layer and enable the overlay
apply mode. Fill this layer with 50% gray and group it with the
underlying blur layer. Now run the noise filter on this gray layer.
Noise is applied to the underlying smooth skin but ramps off as the
values approach white and black so you get cleaner highlights and shadow areas.

--
regards,

Lee Varis
varis@...
888-964-0024
www.varis.com


Smooth skin?

John Opitz <jas10286@...>
 

<: Smooth Skin?
What's the best way to smooth skin on photos?
Is it bluring AB channels?

Hector Davila>

The Gaussian Blur Filter. Don't make selections to target skin
areas(doing that is like chasing rainbows amd setting traps for
unicorns). Do it to the whole image. Then take a snapshot of this
state. Next undo gaussian blur. Use the history brush in lighten and
darken modes(5-15% opac.) to paint back the areas you want to smooth.
Make sure you click on the snapshot(history state) to paint back from.


John Opitz


Re: UCR vs GCR

Ruud uit het Instituut
 

Oops, to fast..

I wrote
But PCR was in fact the same as the german definition 'unbunt' on the Hell
scanners or the American GCA (Gray Component Addition) and it's opponent
GCR.

Last thing was wrong,
GCR has nothing to do with GCA, it's the same as UCR, I shouldn't mention it
in that sentence.

Ruud de Korte


Re: UCR vs GCR

Ruud uit het Instituut
 

Dan Margulis wrote

We also fall victim to a terminology trap here--there's no real agreement
on what constitutes a "UCR" sep, other than that it's a subset of "GCR".

You're right. IMO the terminology went wrong when vendors started to make
their own definitions. I worked with the old Magnascanners from Crosfield.
There I could choose between UCR and PCR or a combination of those two.
UCR = Under Color Removal
PCR = Poly Color Removal
The difference between those two was that UCR was only active in the
neutrals and PCR in the colors.
But PCR was in fact the same as the german definition 'unbunt' on the Hell
scanners or the American GCA (Gray Component Addition) and it's opponent
GCR.

So UCR and GCR both mean the same and are active in the neutrals (the L axis
in Lab).
PCR, unbunt and GCA are also the same and use the combination of all three
axis in Lab.

Excuse my English, I seem to have a Dutch accent.

Ruud de Korte