Gum Bichromate on Mirror Back #glass #bichromate


LoganCThomas
 

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 


Jeremy Moore
 

Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.

Jeremy@...


On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 

--
Sent from a mobile device.


LoganCThomas
 

Thanks!

Yes you’re right in your interpretation - when writing I didn’t notice the double meaning of “expose” given our context.

I actually would prefer the shadows to be transparent to the viewer (as in being able to look straight through the glass in shadow areas). I don’t intend to use any watercolour pigments in this case. Only using the reflective film of the back of the mirror as my “pigment”.

I’m not sure, but I think your suggestions of using a metal plate and glass plate, and the daguerreotype wouldn’t allow for the transparency I’m looking for.

Do you know of a material that would help me work with the metal film at the back of the mirror? 

Thanks for your help! 

On 30 Aug 2021, at 10:51, Jeremy Moore <alt.photosbyjeremy@...> wrote:


Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.

Jeremy@...


On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 

--
Sent from a mobile device.


Pfriedrichsen
 

Hi Logan, 

If you do go this route, I hope you will be able to get the gum to stick. Mirrored silver does not have much to offer for adhesion. Gum hardens from the top down, so at best and assuming you get any adhesion at all, you will have no grey scale if that is a concern.

For acid etch, maybe nitric acid as etchant but a safety risk there with nitrogen dioxide and the nitric fumes. Maybe there is a safer etchant, and not sure if the hardened gum would hold up to something so aggressive. 

Its a challenge for sure!
Peter

On Aug 30, 2021, at 1:19 PM, LoganCThomas <logancthomas@...> wrote:

 Thanks!

Yes you’re right in your interpretation - when writing I didn’t notice the double meaning of “expose” given our context.

I actually would prefer the shadows to be transparent to the viewer (as in being able to look straight through the glass in shadow areas). I don’t intend to use any watercolour pigments in this case. Only using the reflective film of the back of the mirror as my “pigment”.

I’m not sure, but I think your suggestions of using a metal plate and glass plate, and the daguerreotype wouldn’t allow for the transparency I’m looking for.

Do you know of a material that would help me work with the metal film at the back of the mirror? 

Thanks for your help! 

On 30 Aug 2021, at 10:51, Jeremy Moore <alt.photosbyjeremy@...> wrote:


Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.

Jeremy@...


On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 

--
Sent from a mobile device.


brittonie,
 

If it’s the mirror film- that’s a sortof plastic on more contemporary mirrors… 

Might even find for “photomechanical” process going the route of a laser cutter  or a cnc to get through that plastic film rather than etching through it.

On Mon, 30 Aug 2021 at 13:41, Pfriedrichsen <pfriedrichsen@...> wrote:
Hi Logan, 

If you do go this route, I hope you will be able to get the gum to stick. Mirrored silver does not have much to offer for adhesion. Gum hardens from the top down, so at best and assuming you get any adhesion at all, you will have no grey scale if that is a concern.

For acid etch, maybe nitric acid as etchant but a safety risk there with nitrogen dioxide and the nitric fumes. Maybe there is a safer etchant, and not sure if the hardened gum would hold up to something so aggressive. 

Its a challenge for sure!
Peter

On Aug 30, 2021, at 1:19 PM, LoganCThomas <logancthomas@...> wrote:

 Thanks!

Yes you’re right in your interpretation - when writing I didn’t notice the double meaning of “expose” given our context.

I actually would prefer the shadows to be transparent to the viewer (as in being able to look straight through the glass in shadow areas). I don’t intend to use any watercolour pigments in this case. Only using the reflective film of the back of the mirror as my “pigment”.

I’m not sure, but I think your suggestions of using a metal plate and glass plate, and the daguerreotype wouldn’t allow for the transparency I’m looking for.

Do you know of a material that would help me work with the metal film at the back of the mirror? 

Thanks for your help! 

On 30 Aug 2021, at 10:51, Jeremy Moore <alt.photosbyjeremy@...> wrote:


Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.

Jeremy@...


On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 

--
Sent from a mobile device.

--



BrittonieFletcher.com


Jeremy Moore
 

I suggested printing on a reflective metal plate that you adhere glass to because that’s how mirrors are made. Instead of trying to take a mirror apart, remove a section, then put it back together you would just make a mirror with the image in the middle.

This, I think is where I’m getting lost with your description—how are you planning on printing a full-tone image on the front of the reflective metal where it is adhered to the glass?

Are you thinking of working from the back through the metal using a halftone— So where the halftone “prints” you’d etch all the way through the reflective coating?

On Mon, Aug 30, 2021 at 1:19 PM LoganCThomas <logancthomas@...> wrote:
Thanks!

Yes you’re right in your interpretation - when writing I didn’t notice the double meaning of “expose” given our context.

I actually would prefer the shadows to be transparent to the viewer (as in being able to look straight through the glass in shadow areas). I don’t intend to use any watercolour pigments in this case. Only using the reflective film of the back of the mirror as my “pigment”.

I’m not sure, but I think your suggestions of using a metal plate and glass plate, and the daguerreotype wouldn’t allow for the transparency I’m looking for.

Do you know of a material that would help me work with the metal film at the back of the mirror? 

Thanks for your help! 

On 30 Aug 2021, at 10:51, Jeremy Moore <alt.photosbyjeremy@...> wrote:


Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.

Jeremy@...


On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 

--
Sent from a mobile device.

--
Sent from a mobile device.


Laurence Patrick Cuffe,
 

This Video, gives a little insight into modern mirror making:
Its seems you get a coating with the following layers Glass:Tin:Silver:Copper:Paint:paint.
The first step might be to remove the paint with some combination of organic solvents. 
I wonder if you couldn’t follow that with Some thing like the Heliograph process, where you use pitch to make an acid resist, which could be etched through to get the get your clear sections.
Just a thought.
Laurence Cuffe


On 30 Aug 2021, at 19:45, Jeremy Moore <alt.photosbyjeremy@...> wrote:

I suggested printing on a reflective metal plate that you adhere glass to because that’s how mirrors are made. Instead of trying to take a mirror apart, remove a section, then put it back together you would just make a mirror with the image in the middle.

This, I think is where I’m getting lost with your description—how are you planning on printing a full-tone image on the front of the reflective metal where it is adhered to the glass?

Are you thinking of working from the back through the metal using a halftone— So where the halftone “prints” you’d etch all the way through the reflective coating?

On Mon, Aug 30, 2021 at 1:19 PM LoganCThomas <logancthomas@...> wrote:
Thanks!

Yes you’re right in your interpretation - when writing I didn’t notice the double meaning of “expose” given our context.

I actually would prefer the shadows to be transparent to the viewer (as in being able to look straight through the glass in shadow areas). I don’t intend to use any watercolour pigments in this case. Only using the reflective film of the back of the mirror as my “pigment”.

I’m not sure, but I think your suggestions of using a metal plate and glass plate, and the daguerreotype wouldn’t allow for the transparency I’m looking for.

Do you know of a material that would help me work with the metal film at the back of the mirror? 

Thanks for your help! 

On 30 Aug 2021, at 10:51, Jeremy Moore <alt.photosbyjeremy@...> wrote:


Welcome to the list, Logan!

I need some help understanding as I think my photo brain keeps getting confused because “expose the metal film” just means “reveal the metal film”, right? 

Regardless, it sounds like want watercolor pigment for shadows and reflective metal highlights. Are you after the final look or is the process you’ve described essential to your work?

It seems simpler to start with the reflective metal and glass as 2 separate pieces than a finished mirror you have to take apart and put back together. Is there a reason you’re deconstructing a mirror instead of making one?

Also, have you thought of printing a daguerreotype then trying gum on top? That would give mirrored highlights.



On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 



--
Sent from a mobile device.


--
Sent from a mobile device.


Frank Gorga
 

Logan,

I hate to be pessimistic and to inhibit experimentation, but I doubt that what you want to do is chemically possible.

If I understand you correctly you want to find a method for removing the metal film from a glass mirror while keeping a hardened gum layer intact. Is that correct?

If so, I am not sure that it is possible. Removing the metal layer will require a strong mineral acid (concentrated nitric or sulphuric most likely; the most effective acid would depend on what metal has been used to make the mirror). 

However, an organic polymer such as gum arabic is very susceptible to hydrolysis by strong acids even after it has been crosslinked (hardened) with light and dichromate. 

Thus I doubt that you will be able to find conditions where you can keep the gum layer intact while removing the metal.

Regards,

--- Frank

P.S. None of the above information comes from any direct experience. It is based on my intuition developed over a career working as a chemist. (I am retired now.)

On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 


Kurt Nagy
 

You may have better luck with a different process like Wet Plate.  A friend of mines MFA portfolio was wet plate ambrotypes on mirrors and the result was similar to what you're describing.  Depending on the angle the work was viewed at determined how strong the image was vs your reflection


From: altphotolist@groups.io <altphotolist@groups.io> on behalf of Frank Gorga <fgorga@...>
Sent: Monday, August 30, 2021 4:58:21 PM
To: altphotolist@groups.io <altphotolist@groups.io>
Subject: Re: [altphotolist] Gum Bichromate on Mirror Back #glass #bichromate
 
Logan,

I hate to be pessimistic and to inhibit experimentation, but I doubt that what you want to do is chemically possible.

If I understand you correctly you want to find a method for removing the metal film from a glass mirror while keeping a hardened gum layer intact. Is that correct?

If so, I am not sure that it is possible. Removing the metal layer will require a strong mineral acid (concentrated nitric or sulphuric most likely; the most effective acid would depend on what metal has been used to make the mirror). 

However, an organic polymer such as gum arabic is very susceptible to hydrolysis by strong acids even after it has been crosslinked (hardened) with light and dichromate. 

Thus I doubt that you will be able to find conditions where you can keep the gum layer intact while removing the metal.

Regards,

--- Frank

P.S. None of the above information comes from any direct experience. It is based on my intuition developed over a career working as a chemist. (I am retired now.)

On Mon, Aug 30, 2021 at 9:28 AM LoganCThomas <logancthomas@...> wrote:

Hi All, 

I’m new to this forum, and am trying to figure out the best approach to do the following:

My intention is to remove the protective layer on the back of a mirror, to expose the metal film, and then print a gum bichromate positive image (digital negative) on that metal film with the intent of using an acid etch to remove the “shadows”, or the spots that were not exposed. The idea is to produce an intentionally ‘antiqued’ mirror-print. Where the highlights of my image would be the reflective mirror, and the shadows would be filled in using a paint/material of choice. 


Does anyone have experience doing this? Or have any guidance as to how it might be achieved? 


LoganCThomas
 

Thanks for your insight Frank, an understanding of chemistry to the degree that you must is something that I sorely lack.

I did my first experiment with removing the paint layers on the back of the mirror yesterday to find that the metal layers underneath are very delicate compared to the paint. The solvent I used to remove the paint removed some of the metal without much effort on my part, but using a diluted muriatic acid (I do not know the dilution right now - I was working intuitively) seems to weaken the metal quite quickly and allow for it to be washed off within seconds.

My thought is that if I were to go ahead with using bichromate, that it might work, but I would need to use something that spreads over glass better, and would have to make it quick and ensure that the sensitized mirror plate is exposed using a high contrast, high-density negative, developed well and then dried in the sun. However, my issue is still getting the solution to spread evenly on the surface. I was wondering if Casein could work as a good substitute for gum arabic. I've read elsewhere that it spreads over glass much easier. Do you have any experience with that?

"Brittonie" offered a solution using a photopolymer film that seems like it might be the best solution for my situation. I'm going to look into this option more.

Thank you again for your input, and helping me to think out this problem.

 

 


Jorj Bauer
 

I've printed extensively with casein on glass. It definitely adheres to glass better than gum. It takes some practice to be able to apply it in a way that doesn't streak, but I've also used the streaking to effect like in this one -

  https://blog.k8s.jorj.org/?p=2537

I like working it while it dries to prevent it from pooling, and working it in alternating directions helped reduce the streaking.

-- j

On 8/31/21 7:41 AM, LoganCThomas wrote:

Thanks for your insight Frank, an understanding of chemistry to the degree that you must is something that I sorely lack.

I did my first experiment with removing the paint layers on the back of the mirror yesterday to find that the metal layers underneath are very delicate compared to the paint. The solvent I used to remove the paint removed some of the metal without much effort on my part, but using a diluted muriatic acid (I do not know the dilution right now - I was working intuitively) seems to weaken the metal quite quickly and allow for it to be washed off within seconds.

My thought is that if I were to go ahead with using bichromate, that it might work, but I would need to use something that spreads over glass better, and would have to make it quick and ensure that the sensitized mirror plate is exposed using a high contrast, high-density negative, developed well and then dried in the sun. However, my issue is still getting the solution to spread evenly on the surface. I was wondering if Casein could work as a good substitute for gum arabic. I've read elsewhere that it spreads over glass much easier. Do you have any experience with that?

"Brittonie" offered a solution using a photopolymer film that seems like it might be the best solution for my situation. I'm going to look into this option more.

Thank you again for your input, and helping me to think out this problem.


LoganCThomas
 

HI Lawrence,

Thanks for the information - I did my first experiment removing the paint yesterday and could clearly see the three layers of metal. I was too heavy-handed with the paint remover, but it was an ok first try. I like your suggestion of using a heliograph, I imagine that would work well for the glass. I'll have to locate a decent tutorial on how that's done, and then see how I might get the chemistry into Barbados.

 

Thanks again,
Logan


LoganCThomas
 

Jorj,

Your attached blog post is the reason I'd considered casein in the first place, thank you for that!

In terms of how you source your casein, I've had difficulty finding a source that isn't just protein powder for bulking up muscles. Is that what you use?


Jorj Bauer
 

I got mine from a company that I think I stumbled across while looking at milk paints. Looks like they're still in business - earthpigments.com. I literally bought enough from them in one go that I've made many hundreds of prints, if not a thousand. My printing studio (read: basement) is like a graveyard for boxes of 8x10 glass plates I didn't quite like and will eventually scrub off to re-use the glass :)

-- j

On 8/31/21 7:56 AM, LoganCThomas wrote:

Jorj,

Your attached blog post is the reason I'd considered casein in the first place, thank you for that!

In terms of how you source your casein, I've had difficulty finding a source that isn't just protein powder for bulking up muscles. Is that what you use?


LoganCThomas
 

Thanks for this!


LoganCThomas
 

Hi Brittonie,

Thank you for sharing the link to the photopolymer film, I have a feeling that this might be the right direction for me to go in.

I can't find the link in this thread anymore so I'm attaching it here for anyone else who may need this info in the future.

https://www.amazon.com/VANTIYAUS-Photosensitive-30cmx500cm-1ftx16-5ft-Photoresist/dp/B01NCS88LU/ref=asc_df_B01NCS88LU/?tag=hyprod-20&linkCode=df0&hvadid=193160167906&hvpos=&hvnetw=g&hvrand=9962850573850349853&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1018127&hvtargid=pla-306079767565&psc=1

Logan


Kees Brandenburg,
 

In traditional photogravure a pigment tissue is exposed and transferred to a copper etching plate dusted with an asphaltum ‘grain'. After development the gelatin functions as a resist for the etching acid. It is removed after etching and the plate can be inked, wiped and printed on a press.

So if you found a good way to etch the metal layer of your mirror I would advise to print a single transfer carbon tissue on the mirror back in stead of gum.

Also you can drop the poisonous bichromate and use DAS with carbon. This is the same with caseïn.

best regards,

Kees

My thought is that if I were to go ahead with using bichromate, that it might work, but I would need to use something that spreads over glass better, and would have to make it quick and ensure that the sensitized mirror plate is exposed using a high contrast, high-density negative, developed well and then dried in the sun. However, my issue is still getting the solution to spread evenly on the surface. I was wondering if Casein could work as a good substitute for gum arabic. I've read elsewhere that it spreads over glass much easier. Do you have any experience with that?


Niranjan Patel
 

Can one "etch" plated silver with bleach-fix (K ferricyanide followed by thiosulfate) procedure?  If that's so, harsh acidic etchants can be avoided. 

Photogravure etchant is ferric chloride which may be more benign than an inorganic acid to the organic layer.  If one can get a copper plated glass (don't know,) the process can be similar to making a photogravure plate as Kees suggested.  Or may be even by use of dry film photoresist and following what they do in making a PCB.  Use of halftone negative will help getting a gray scale image as alluded earlier. 

:Niranjan.


ender100
 

How about using this as a resist?



Best Wishes,
Mark Nelson

www.PrecisionDigitalNegatives.com
www.MarkINelsonPhoto.com

Curve Calculator III for the Mac is Now Available

sent from my iPhonetypeDeviceThingy

On Aug 31, 2021, at 7:57 AM, Kees Brandenburg, <workshops@...> wrote:

In traditional photogravure a pigment tissue is exposed and transferred to a copper etching plate dusted with an asphaltum ‘grain'. After development the gelatin functions as a resist for the etching acid. It is removed after etching and the plate can be inked, wiped and printed on a press.

So if you found a good way to etch the metal layer of your mirror I would advise to print a single transfer carbon tissue on the mirror back in stead of gum.

Also you can drop the poisonous bichromate and use DAS with carbon. This is the same with caseïn.

best regards,

Kees

My thought is that if I were to go ahead with using bichromate, that it might work, but I would need to use something that spreads over glass better, and would have to make it quick and ensure that the sensitized mirror plate is exposed using a high contrast, high-density negative, developed well and then dried in the sun. However, my issue is still getting the solution to spread evenly on the surface. I was wondering if Casein could work as a good substitute for gum arabic. I've read elsewhere that it spreads over glass much easier. Do you have any experience with that?






Niranjan Patel
 

On a second thought, isn't the final product in the original idea pretty much equivalent to an orotone - the difference being the order and the type of metallization.  So why not simply make the gum image layer first which can be followed by mirror formation (or tp make it easy, coating a silver paint) instead of dealing with all the subtractive steps involved when starting with a mirror. 

:Niranjan.