Gum Bichromate: Can't get good results

GuidoIlieff said:

I have not. I didn't want to disrespect all the work he has done with that book because 50 dollars seems like a very fair price. But if you say hes approachable I'll try. Is he active in this forum or should I try to contact him on his business mail?

Click to expand...

Are you on Facebook - there is a Facebook group dedicated to gum. I am sure you will get much more help there than 2 guys here - one who never did any gum and another who has given up on it....

:Niranjan.

Yeah, Facebook is proba6a good idea, and you could try the alt printing process group on groups.io: https://groups.io/g/altphotolist/topics I think Calvin reads that one as well, and in any case several others such as Kees Brandenburg do.
Reaching out to Calvin works fine through his business email in my experience.

koraks said:

Yeah, Facebook is proba6a good idea, and you could try the alt printing process group on groups.io: https://groups.io/g/altphotolist/topics I think Calvin reads that one as well, and in any case several others such as Kees Brandenburg do.

Click to expand...

Agree. There are some early practitioners like Christina Anderson and others who have literally wrote the books on the subject.

:Niranjan.

GuidoIlieff said:

oh ok. So there is something wrong in what I do. If I use my brush with the lightest touch and softest brush I remove everything in the print, nothing holds on. That's why I called it aggressive. Thanks for the info!

Click to expand...

I wouldn't say you're doing anything wrong regarding how delicate the image is. That's been exactly my experience also. Most of my gum prints are built up with thin fragile coats, 7 or 8 coats in most cases. If I touch the print with anything at all it ruins the print almost every time unless the damage is so minor that I can print my way through it with the remaining coats. I have no idea how other people are able to brush or spray their prints. My process may be slow but I get sharp and deep prints this way.

Dwayne Martin said:

I wouldn't say you're doing anything wrong regarding how delicate the image is. That's been exactly my experience also. Most of my gum prints are built up with thin fragile coats, 7 or 8 coats in most cases. If I touch the print with anything at all it ruins the print almost every time unless the damage is so minor that I can print my way through it with the remaining coats. I have no idea how other people are able to brush or spray their prints. My process may be slow but I get sharp and deep prints this way.

Click to expand...

Hi. Oh ok so its not only me. Any advice on doing more than 3 layers? I'm currently stuck there.

Also, is there any way to see your work on gum prints?

Thanks!

nmp said:

Agree. There are some early practitioners like Christina Anderson and others who have literally wrote the books on the subject.

:Niranjan.

Click to expand...

I posted on altphotolist and Christina replied to my message! Thanks

Then you're getting the best advice you can probably get

GuidoIlieff said:

Hi. Oh ok so its not only me. Any advice on doing more than 3 layers? I'm currently stuck there.

Also, is there any way to see your work on gum prints?

Thanks!

Click to expand...

Here is an example of what I get with my process. There are more in my port if you would like to see them. All of the gums you’ll see there have an average of 7 coats except for the one titled ”Drifter”, that one only required two coats for some reason.
my experience has been that if you expect to use multiple coats you’re going to need a very accurate system for registration, and a means to control humidity. I work in 65% humidity. It could be any humidity so long as it’s the same each coat. one reason for doing this is because it keeps the paper exactly the same size so the negative matches the print. It also has an effect on exposure but for me that’s less important than the paper size. I print on 16x20 paper, I would expect smaller paper to be less critical. I use shortened thumb tacks for registration, one on each corner. If the paper has moved the tacks won’t fit properly so you know you need to adjust the humidity.
In my case hardened gelatin worked the best. I tried lots of other methods but I didn’t have much luck. Your experience may be different. pre shrinking the paper then sizing will help to stabilize the paper for you to help with registration.

It will likely take you a while to get the hang of laying down a nice coat of emulsion, I know it took me a while…
hope that helps.

Dwayne Martin said:

Here is an example of what I get with my process. There are more in my port if you would like to see them. All of the gums you’ll see there have an average of 7 coats except for the one titled ”Drifter”, that one only required two coats for some reason.
my experience has been that if you expect to use multiple coats you’re going to need a very accurate system for registration, and a means to control humidity. I work in 65% humidity. It could be any humidity so long as it’s the same each coat. one reason for doing this is because it keeps the paper exactly the same size so the negative matches the print. It also has an effect on exposure but for me that’s less important than the paper size. I print on 16x20 paper, I would expect smaller paper to be less critical. I use shortened thumb tacks for registration, one on each corner. If the paper has moved the tacks won’t fit properly so you know you need to adjust the humidity.
In my case hardened gelatin worked the best. I tried lots of other methods but I didn’t have much luck. Your experience may be different. pre shrinking the paper then sizing will help to stabilize the paper for you to help with registration.

It will likely take you a while to get the hang of laying down a nice coat of emulsion, I know it took me a while…
hope that helps.

Click to expand...

WOW! They look amazing! II love the grain in the one titled Drifter. I'm currently using thumb tacks too but I have no way of controlling the humidity, but for now I don't care that much about registration. What I love about this technique is how colors mix.

Do you use gelatin between each layer? I still can't get more than 2 layers. Christina Anderson gave me this advice on another forum:

Christina Z. Anderson
Jul 9 #7978

I see this all the time, the final layer slips off because the surface is too glossy. So I tell students to expose longer with the later layers. Also coat more thinly, add a drop or two more dichromate, and the other potential is to sand the surface with fine grit sandpaper to give it some tooth before the final layer. This needs to be done only in the glossy shadows. But longer exposure definitely helps.
Chris

Click to expand...

Maybe my coats are too thick. I definitely need a better brush.

Final question: Do you coat the gelatin with a brush or do you submerge in gelatin, then coat with formaldehyde?

Thanks

I do submerge the paper in the gelatin but I brush it a bit while it’s in there to prevent dry spots that I was getting. Then I hang them to dry. When they are hanging you have to make sure there are no little tiny air bubbles that don’t drain to the bottom of the paper. you can dab those with a Q tip or something. If you miss one and it dries in the gelatin it will show up in the print. Same goes for any dry spots were the gelatin didn’t soak into the paper evenly. I used to just brush it on but it was too inconsistent so I had a lot of problems. I personally mix glyoxal into the gelatin, I’ve never tried it any other way. I tried to size with pva size between coats but it never worked for me so now I stick to a single coat of hardened gelatin and that’s it. I do have the surface tension issues that cause fish eyes but I’m able to brush them out without too much fuss.

I’ve never had the problem of a coat not adhering as you describe. Interesting what Christina said about sanding the paper. Sounds like that might be a good solution for the fish eyes..

One piece of advice I can give you is figure out the perfect amount of sensitize emulsion for a given negative size. It will make coating much more predictable. When you start brushing the clock is ticking so if you don’t have enough on the paper you will struggle to get it spread at the perfect thickness. For me, too much is better than not enough. In my case 8ml is just right for a print on 16x20 paper for example.

Dwayne