Tag: Darkroom

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

Ammonium vs Potassium Dichromate

October 1, 2015

breadkenty asked: … Also how do you feel about the difference between Ammonium Dichromate vs Potassium Dichromate? After working with the Potassium for a while, I’ve noticed that it gets really messy and muddy when you go any more than 4 layers. I noticed that even with Mr.Gonzalez’s first round of tricolor layers, the image seemed to lack detail and tone, but with the potassium formula you maximize the full tones, contrast, and color by the first round (Cyanotype, M, Y, and C layers). What are your thoughts?

I’ve been using the Ammonium Dichromate for over 10 years–that’s what I’ve used for all my tests and I’m pleased with the way the prints come out in color, tone and density .  I experimented with the Potassium Dichromate once and had terrible results.  So, I decided to stick with what I know.

Paper weight

October 1, 2015

breadkenty asked: Hi Tony, thank you for all the previous advice regarding gum printing. I am now in the process of putting together a show with twenty to thirty 14x20in prints from the same negative repeating across the gallery space (like Warhol). I start to consider price and efficiency when working with many prints. I switched from Arches Platine to Artistico Fabiano 140lb and noticed the paper is a lot weaker and prone to tearing. I considered BFK but that is still a bit pricy. What would you recommend?

Yes, I think the 140lb weight may not be heavy enough.  I use the 250 gram Rives BFK and that seems to hold up ok.  In the past I’ve tried the Lana Aquarelle paper with limited success.  I’m not sure how the cost for the Lana compares with the Rives or the papers you’re using.

Gum:Sensitizer ratios

August 4, 2015

windeking asked: I have a few questions about your calibration technique. Did you calibrate for each color? When you did the calibration, how did you determine how long to expose the step wedge? Did you do multiple exposures with the different ratios of gum to sensitizer? In the third set of exposures of your workflow, you say to expose just long enough to achieve tone in step three, but you already have tone up to step eight from set 2. Am I misunderstanding something? Thanks Alan

The exposure times are a result of experiments with different gum:sensitizer ratios with multiple layers.  The exposure time, development and ratio I use are the same for all three colors–with the exception of cyan where I tend to use a slightly shorter exposure time (about 15-30 secs shorter) than the yellow and magenta.  The third set is a short exposure which adds additional color and tone in the shadows for enhanced D-max.  Hope this helps.  Tony

Gum over Van Dyke Brown (part 1)

February 18, 2015

breadkenty asked: Hi Tony, I’m trying to recreate something similar to Edward Steichen’s Gum over Platinum prints for his Camera Work/Vogue Fashion prints. I really like the sharp details that the Platinum print offer with the grain of gum prints over it but I am looking for an alternative to Platinum printing that wont be as expensive. I was thinking Van Dyke but do you have any previous experiences with Gum over Van Dyke or any other processes outside of Cyanotype? If so, what color paint would be best for gum?

I did a lot of Van Dyke before I started doing Gum–but, I haven’t tried Gum over Van Dyke.  Although, I don’t see why it wouldn’t work.  As far as color, in prints of the “Flat Iron Building” and “The Pond, Moonlit” Steichen often used cool colors (i.e. blues, greens etc.) to compliment the brown of the Van Dyke.  That might be a good place to start.  Tony

Printing the black layer

September 25, 2014

tylerjacobsen asked: Hi Tony, Your gum bichromate prints are beautiful! I’m a photographer and I’m going to start making gum prints. Your blog has been very informative. I do have a question; For the k or black exposure (layer) which neg are you using? In your description of making digital negs (invert, convert to multicolor, split channels), I get 3 separate files, cyan, magenta, and yellow, but no gray channel.

Thanks for the compliment.  For printing black, I use the “C” negative with a short exposure at the very end with WN Lamp Black.  I do three color separations to produce cyan, yellow and magenta negatives. There is no gray negative.  Some people prefer to do four color separations to get cyan, yellow, magenta and a black negative.  All of the test I’ve done for my prints have been with the three color (C,Y and M) negatives.  Hope this helps.  

Tony