Difference between Ammonium and Potassium Dichromate

March 31, 2019

darkroom-dave asked: Hey Tony, I was curious about the differences between potassium bichromate and ammonium bichromate and why you use the later.

I find the Potassium Dichromate doesn’t dissolve as well as the Ammonium Dichromate.  Apparently, Potassium Dichromate produces less contrast but I can control the contrast in my print by varying the ration of Gum Arabic to Sensitizer using Ammonium Dichromate.

Step tablets

August 21, 2018

fallingkind asked: Hello there Tony, I am an Photo/art Grad student at Texas A&M Corpus Christi University, my name is Joshua Dancause. I am such a fan of your brilliant work with Gum bichromates. I have been researching your workflow and stumbled upon your Tumblr through youtube. I found that someone had asked you about your registrations marks and step tablets and how they were made etc. In your post you had mentioned if they emailed you, you would send them a tiff file, could you do the same for me? Best, Josh

Thank you.  Send me an email gonoma@mac.com and I can email you the TIFF files.

Pre-shrinking

September 8, 2016

oldsoulslove asked: I was looking through your archive for tips on Gum printing. I was wondering how you prevent against paper shrinkage with so many layers of gum and cyanotype. I did notice in one post that you said you do not used any backing. Also, do you size your paper and how so? Thanks in advance!

Check out my post on pre-shrinking and sizing.

https://wordpress.com/block-editor/post/thegumbichromatejournal.com/84

oldsoulslove asked: Your work is beautiful BTW

Thank you!

RGB curve for B&W prints

July 8, 2016

a-cheers-blog asked: Hi Tony, Thank you for your sharing your experiences with us, you have mastered this craft. I have a couple of question about monochrome printing. Can we use the RGB curve that you have introduced in other posts for black & white printing too?? or we need to make a new curve specifically for B&W? how many layers usually you end up with in B&W. And also what brand you suggest for black pigments? Thank you

Thank you for your comments about my work.  Yes, you can use the RGB curve for B&W printing too–especially if you’re going to use multiple layers.  I do not use a curve specifically for B&W printing.  I have used the Winsor Newton “Lamp Black” for my black pigment.  Hope this helps.  Tony

On adhering onto aluminum (part 1)

February 19, 2016

safakoncu asked: Hello again, I apologize to ask again and again but what I wonder was is there a backing to your print (during process) and do you remove it when printing is done. Some people glue their paper to aluminum sheet, in your sample photographs I see some blue material at the back of print. I wondered what was it and how to remove when printing process is over. Thanks again for your patience. (sorry my native language is not English and I might not expressed what I ask in correct way previously).

No worries, I believe I understand your question now. I’m not sure what blue material you’re seeing in my sample photographs, but I do not glue my paper to an aluminum sheet or any support material.  I use the Rives BFK sheet alone with the negatives when I print.  Hope this helps.  Tony

Rives BFK

February 19, 2016

safakoncu asked: Hello again, I meant the paper you use is sticks to a blue medium like plastic sheet, how to stick our paper to that medium and how to remove when print is completed. I did cyanotypes and will try gum bichromate, everything ready just waiting for good weather to come (I do not have UV lightbox yet) Thanks again for answering and sharing your knowledge with us.

I use Rives BFK watercolor paper for my prints.  I place my Pictorico negative on top of the coated paper and put inside a vacuum table underneath my exposure unit to make my exposures.