Has anyone else here tried Gumoil?

[Andrew O'Neill]

Here's a pic of the wet matrix, dried, and a close up... I inked up the dried matrix and let it sit over night. Sat the print in room temperature water and wiped of ink with damp sponge. There was no advantage to letting ink sit longer. I'll post a snap of it when it has dried. I'm going to try a cold press paper next.

 

[Andrew O'Neill]

I chucked out that last print. Pretty ugly. I decided to make a couple of changes. First, I increased the PD from 16% to 20%. Second, I coated the 20% PD sensitized gum arabic onto Stonehenge. I ended up with the best print ever. Quite pleased. Here it is...

 

[NedL]

well done!

 

[Andrew O'Neill]

Thanks, Ned! I gave up on this process, but the urge was building to get back at it and try again. Now that I know I can do it, I can try different things with it for fun.

 

[julesaq]

Thanks, Ned! I gave up on this process, but the urge was building to get back at it and try again. Now that I know I can do it, I can try different things with it for fun.

I'm new to this process. I thought potassium bichromate saturated soln is b/w 10 to 13% vs ammonium bichromate saturated soln can reach 27 to 29%. So which of the salt form are you using to reach your best print? Are you still using 1:3 proportions with gum? What paper did you switch from? What type of uv exposure source and time exposure for your print? I'm failing miserably using 1:3 proportion with ammonium bichrom 15% on Arches aquarelle and waiting for some Somerset satin paper to come in the mail. Also not sure if I'm overexposing my paper with the uv exposure unit to cause the gum to harden too much such that there's no gum open areas for oil paint to absorb into paper. How did you determine your exposure time....maybe that's also a problem I'm trying to figure out...despite reading Koenigs book.

 

[ced]

Lovely print Andrew!

 

[Andrew O'Neill]

Yes, good catch. I used ammonium dichromate! Was just so used to used PD for gumoils. Sorry about that. In regards to paper, I mentioned what I was using in previous page, I believe. It was Fabriano Artistico. Yes, still using 1:3 dilution. Using a foam roller to apply it. Much better than a brush. I did a test strip to determine exposure. I soaked the print in 24C water for 20 minutes. It's done when the hardened areas are in relief. If you don't see relief, leave it in the water longer. I frequently change the water as dichromate leaches out. Then I Dry the print, ink it, wipe off, (no wait time) stick in water straight from the tap (it's cold!) for a minute, take out and gently wipe with damp sponge.

 

[glpozza]

Thank you for the detailed explanation. I'll soon try again, but I believe my gum is not hard enough for such relief.

 

[julesaq]

Yes, good catch. I used ammonium dichromate! Was just so used to used PD for gumoils. Sorry about that. In regards to paper, I mentioned what I was using in previous page, I believe. It was Fabriano Artistico. Yes, still using 1:3 dilution. Using a foam roller to apply it. Much better than a brush. I did a test strip to determine exposure. I soaked the print in 24C water for 20 minutes. It's done when the hardened areas are in relief. If you don't see relief, leave it in the water longer. I frequently change the water as dichromate leaches out. Then I Dry the print, ink it, wipe off, (no wait time) stick in water straight from the tap (it's cold!) for a minute, take out and gently wipe with damp sponge.

I just tried out with Somerset paper working with inkjet positive transparency. When the final print came out after inking with oilprint, I realized that it was a negative print and not a positive print. All my highlights became shadows and shadows became highlights. It's not even logical. I also printed it with Stauffers step wedge which however maintained as positive on the print. Not sure what I'm doing wrong with the gumoil. I was experimenting with 3 different proportions-1:2, 1:2.5, and 1:3. But now I'm really confused with process. I will try experimenting with a negative transparency and see if it will become a positive print.

 

[ced]

Here is an interesting write up of her experience(great images and lots of info).
Seems this pos/neg inversion is possible as experienced by another photographer see comments below the blog.
http://kelzoshead.blogspot.be/2016/02/gumoil.html

 

[TheToadMen]

Here's a Youtube film about how it's done by Karl Koening (28 minutes):

 

[Andrew O'Neill]

Thanks. I've watched that video several times. I follow what he does although I do not bleach.

 

[Andrew O'Neill]

Julesaq, you have to work with a positive image, not a negative...

 

[mmeshka]

Well, after several unsuccessful attempts, I think I got it. My first successful gumoil print on Canson Moulin du Roy paper.
I have tried different dichromates - potasium dichromate, amonium dichromate, potasium dichromate with some aqua amonia. They all work. Just you have to adjust the exposure time.
https://www.flickr.com/photos/46936779@N08/28670647274/in/dateposted-public/

 

[NedL]

Welcome to APUG! That's great!

 

[mmeshka]

One more try of Gumoil printing. Not the worst attempt. But a lot to learn from it. Small details are not for gumoil printing. Canson Moulin du Roy paper leaves tiny mesh-like marks and it is not easy to wash away the oilpaint from exposed areas. I need to change it.
https://www.flickr.com/photos/46936779@N08/29367447556/in/dateposted-public/

 

[ced]

I think it is a lovely print! For the mesh try a small gaussian blur or add noise in PS...

 

[Andrew O'Neill]

Can't talk about deegeetul here...