Wavelength for all Alt. Processes ?


Michael
 

I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Kurt Nagy
 

365nm to 395nm

365 is optimal for exposure time but more expensive cost wise.


From: altphotolist@groups.io <altphotolist@groups.io> on behalf of Michael <pixelwaster@...>
Sent: Sunday, September 5, 2021 2:13:34 PM
To: altphotolist@groups.io <altphotolist@groups.io>
Subject: [altphotolist] Wavelength for all Alt. Processes ?
 
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Tomas Sobota
 

If you build your exposure unit with led strips, a good idea is to use alternate strips of 360nm and 400nm leds. This arrangement will probably work for every known process. 360nm leds are much more expensive than 400nm though.
Tom


Eric Neilsen
 

I alternate  360 nm with 420 super actinic bulbs  peaking bulbs … 

. So I may not recall what, when, why.... Confirm again later 



On Sep 5, 2021, at 3:32 PM, Kurt Nagy <kakarott76@...> wrote:


365nm to 395nm

365 is optimal for exposure time but more expensive cost wise.

From: altphotolist@groups.io <altphotolist@groups.io> on behalf of Michael <pixelwaster@...>
Sent: Sunday, September 5, 2021 2:13:34 PM
To: altphotolist@groups.io <altphotolist@groups.io>
Subject: [altphotolist] Wavelength for all Alt. Processes ?
 
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Frank Gorga
 

My experience...

Processes that use the photo reduction of iron(III) to iron(II) are broadly sensitive to light at around 390 nm. Thus they work just fine with inexpensive BLB bulbs/LEDs. These sources also seem to work well for salted-paper. 

Photopolymer gravure does not work with the BLB sources, as it requires the shorter wavelengths of the more expensive 360 nm sources. I have no information on how the 360 nm sources work with the iron based processes, but they do seem to work for salted-paper. 

These days I use a simple plywood box with four strips of inexpensive,  pre-wired BLB LED strips which gives me 10 or 15 min exposure times for cyanotype and salted-paper. 

The nice thing about BLB LEDs is you don't need to really worry about managing the waste heat. My box has a few vent holes leftover from when it had fluorescent bulbs but no fan. It barely gets above ambient temperature by 15 min.

--- Frank 


On Sun, Sep 5, 2021, 3:13 PM Michael <pixelwaster@...> wrote:
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Michael
 

Thanks to those who replied and those who are going to.

The photopolymer not responding to BLB may be the reason I am having issues with my PCB etching masks exposure unit. It has a small fluorescent bulb and worked with the old spray-on system.

Multi-function light box.

Thanks again!


Scott Davis
 

I went with blacklight LEDs in my revamped exposure unit. They’re in the 380-390 range. I went a little overkill but I wanted to ensure even coverage for the largest possible prints I could make- I can go up to 16x20. So I have 16 strips of 22” length. My exposure times are 2 minutes now, down from 12+ with fluorescent bulbs, and more consistent. I’m printing palladium mostly at this point, with the odd cyanotype thrown in. Will be doing gum over pt/pd in the near future. 


On Sep 6, 2021, at 9:13 AM, Frank Gorga <fgorga@...> wrote:


My experience...

Processes that use the photo reduction of iron(III) to iron(II) are broadly sensitive to light at around 390 nm. Thus they work just fine with inexpensive BLB bulbs/LEDs. These sources also seem to work well for salted-paper. 

Photopolymer gravure does not work with the BLB sources, as it requires the shorter wavelengths of the more expensive 360 nm sources. I have no information on how the 360 nm sources work with the iron based processes, but they do seem to work for salted-paper. 

These days I use a simple plywood box with four strips of inexpensive,  pre-wired BLB LED strips which gives me 10 or 15 min exposure times for cyanotype and salted-paper. 

The nice thing about BLB LEDs is you don't need to really worry about managing the waste heat. My box has a few vent holes leftover from when it had fluorescent bulbs but no fan. It barely gets above ambient temperature by 15 min.

--- Frank 

On Sun, Sep 5, 2021, 3:13 PM Michael <pixelwaster@...> wrote:
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Terry Glass
 

Would these units work for UV exposure? They are rated 390-400nm



All the Best,
Terry Glass

On Sep 7, 2021, at 4:01 AM, Scott Davis via groups.io <Scotttdavis@...> wrote:

I went with blacklight LEDs in my revamped exposure unit. They’re in the 380-390 range. I went a little overkill but I wanted to ensure even coverage for the largest possible prints I could make- I can go up to 16x20. So I have 16 strips of 22” length. My exposure times are 2 minutes now, down from 12+ with fluorescent bulbs, and more consistent. I’m printing palladium mostly at this point, with the odd cyanotype thrown in. Will be doing gum over pt/pd in the near future. 


On Sep 6, 2021, at 9:13 AM, Frank Gorga <fgorga@...> wrote:


My experience...

Processes that use the photo reduction of iron(III) to iron(II) are broadly sensitive to light at around 390 nm. Thus they work just fine with inexpensive BLB bulbs/LEDs. These sources also seem to work well for salted-paper. 

Photopolymer gravure does not work with the BLB sources, as it requires the shorter wavelengths of the more expensive 360 nm sources. I have no information on how the 360 nm sources work with the iron based processes, but they do seem to work for salted-paper. 

These days I use a simple plywood box with four strips of inexpensive,  pre-wired BLB LED strips which gives me 10 or 15 min exposure times for cyanotype and salted-paper. 

The nice thing about BLB LEDs is you don't need to really worry about managing the waste heat. My box has a few vent holes leftover from when it had fluorescent bulbs but no fan. It barely gets above ambient temperature by 15 min.

--- Frank 

On Sun, Sep 5, 2021, 3:13 PM Michael <pixelwaster@...> wrote:
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.


Terry Glass
 

Should be 385-400nm!

All the Best,
Terry Glass

On Sep 7, 2021, at 6:23 PM, Terry Glass via groups.io <terrygla@...> wrote:

Would these units work for UV exposure? They are rated 390-400nm



All the Best,
Terry Glass

On Sep 7, 2021, at 4:01 AM, Scott Davis via groups.io <Scotttdavis@...> wrote:

I went with blacklight LEDs in my revamped exposure unit. They’re in the 380-390 range. I went a little overkill but I wanted to ensure even coverage for the largest possible prints I could make- I can go up to 16x20. So I have 16 strips of 22” length. My exposure times are 2 minutes now, down from 12+ with fluorescent bulbs, and more consistent. I’m printing palladium mostly at this point, with the odd cyanotype thrown in. Will be doing gum over pt/pd in the near future. 


On Sep 6, 2021, at 9:13 AM, Frank Gorga <fgorga@...> wrote:


My experience...

Processes that use the photo reduction of iron(III) to iron(II) are broadly sensitive to light at around 390 nm. Thus they work just fine with inexpensive BLB bulbs/LEDs. These sources also seem to work well for salted-paper. 

Photopolymer gravure does not work with the BLB sources, as it requires the shorter wavelengths of the more expensive 360 nm sources. I have no information on how the 360 nm sources work with the iron based processes, but they do seem to work for salted-paper. 

These days I use a simple plywood box with four strips of inexpensive,  pre-wired BLB LED strips which gives me 10 or 15 min exposure times for cyanotype and salted-paper. 

The nice thing about BLB LEDs is you don't need to really worry about managing the waste heat. My box has a few vent holes leftover from when it had fluorescent bulbs but no fan. It barely gets above ambient temperature by 15 min.

--- Frank 

On Sun, Sep 5, 2021, 3:13 PM Michael <pixelwaster@...> wrote:
I used to have a nice list of what range of light worked with what process.  I suspect it is on the drive that died.

I am looking to make a new one because I've seen youtubers use everything from 360nm (monochromatic)  to white light from a 500 watt tungsten spot. they all have short (<15 min) exposure times. I just would like to make an exposure box with the right light to start with.