Tag: gum printing

Step tablets

April 23, 2012

pleasekillmenowforiamworthless asked: Hi, I am a student at Utah State and I am hoping you can give me a few tips. I have been looking at your workflow for negatives and I am wondering where you got the files for your registration marks and the step tablets? I have been having a hard time with registration and I am looking for a better method. Second, I am using a NUARC machine for exposure, do you have any experience with those units? I am trying to nail down a good exposure time for each layer.

I found the registration marks I use online years ago and I make my own step tablets in Photoshops by combining layers of rectangles filled with different percentages of black ink to correspond to the outputs of my curve.  If you send me an email agonzale@qc1.qc.edu  I can send you TIFF files of the registration marks and step tablets.  I haven’t used a NUARC machine for exposure for gum printing.  However, I tell my students to test and base their exposure times on the steps on the step tablet since everyone’s exposure unit and development method is different.

Workshops

April 23, 2012

akewaldronart asked: Hey man. Your work is incredible. I’m just about to start trying some alt. pro. stuff and you are definitely going to be an inspiration. If you ever do any workshops or anything I’d love to check one out. – Jake

Thanks a lot.  I don’t have any workshops scheduled, but I will definitely announce any that come up. – Tony

Double coating

March 11, 2012

allcolorlightblog-blog asked: wondering about double coating large gum prints with emulsion+pigment…waiting for first application to dry, then recoating. have you ever tried? does it sound like it would work or do you think that the pigment will fall out of the print?

I haven’t tried double coating.  My sense is that it wouldn’t work as the second coat wouldn’t have anything to hold onto except the unexposed layer underneath and would most likely wash out when developed.  Let me know if you have any success.

Multichannel

February 29, 2012

nonetodate asked: On your 1 Nov 2011 post concerning preparing “The Image for Multichannel” you mentioned you adjust the image for color balance (-35 Cyan and ? for Yellow). You also mention that you boost the saturation by 30%. On your 25 Jan 2012post regarding your “Gum Bichromate Workflow 2012” it states the Cyan layer is changed by -25 and saturation is boosted by 30%. Do you still modify the yellow by a certain %? Why do you do this on the image? Do you use the same amounts per ever image? Thanks!

I’m now going with the new adjustments of -25 C and +30 on the saturation and leaving the Y alone.  I modify the image to compensate for how it changes after you apply the Multichannel so that the print ends up having the same saturation and color balance of the original image. Yes, I have been and will be using the same amount for every photograph.

Glyoxal dilution

February 24, 2012

nonetodate asked: I know you said that you use Glyoxal as your paper hardener. Do you use this straight or is it diluted? Also, how many coats do you put onto the paper and is it reapplied after a few coats of the pigment colors have been applied?

I mix up about 20 ml of 40% Glyoxal per liter of tap water and sometimes add ½ teaspoon of baking soda per liter.   I use up to about a dozen individual layers of sensitizer and pigment.   Staring with Magenta, then Yellow and Cyan, each layer takes about 1 ½ hours to coat, expose, develop and dry before I apply the next layer.  I usually work on several prints at a time over the course of two days (aprox. 20 hours or so.) 

Ratios and exposure times

February 21, 2012

nonetodate asked: I have enjoyed the gum work and discussion.  

I do have a few questions regarding your process:

What amount of pigment do you put into the gum and how much gum is used?

Do you vary this ratio depending on the pigment color?

Do you use the same exposure time for each color pigment or do you vary it when you’re doing those multi layer prints?

Thanks.  Starting with the Magenta negative I mix equal parts (1:1) of Ammonium Dichromate sensitizer with Gum Arabic (12 dropper stems of each or 12:12) and about and inch of pigment (Schmincke Pthalo Blue for the cyan, Permanent Carmine for the magenta and Cadmium Yellow Middle for the Yellow).  I don’t change the ratio for the pigment but I do change it to achieve greater contrast (i.e. increasing the Gum to Sensitizer ratio to 13:11 and then 14:10).  I vary the exposure for the different “sets” of layers.  The first set of M, Y & C is a short exposure (no greater than step 3), the second set of M, Y & C is a long exposure (no greater than step 8), the final set is a short exposure again (no more than step 3) and the black is a really short exposure (about 30 seconds).  Actual times may vary depending on the exposure unit you’re using, pigments, negatives etc.  You can check out my post “Gum Bichromate Workflow 2012 ©” from January for photo illustrations of the process.

Gum techniques

February 15, 2012

fotodude asked: Hi Tony and thanks for sharing many of your Gum techniques. I do have two questions.1) It seems you use six layers for a gum print? Two cyanotypes plus yellow plus red plus blue pigment plus lamp black. If true why the “three” blue type layers and two passes with cyanotype? Your results are incredible.2) Do you develop the print in the “conventional” gum way by placing face down in water for 20 or 30 minutes? Thanks for any comments you provide. Terry Glass, Tipp City OH

Thanks for your interest in my process.  Using the old cyanotype formula, I do two layers of cyanotype in the beginning to enhance the D-max in the print as well as to add detail (one layer of cyanotype may be fine too).  Afterwards, I add the layers of gum with magenta, yellow and cyan (three layers with each color).  Although some of my students stop after the second layer of M, Y & C, I prefer a third layer for deeper shadow tones and greater depth in the print.  I do still development face down for no more than 30 minutes.

Paper

February 13, 2012

allkimik asked: Hello Sir, you cannot imagine the energy and the momentum that this blog fed me last weeks. I wasn’t so pleased with my experimentations with gum, but after reading your material it was like a fresh start for me. I still do some stuff that I found out on my own, and I print my negatives on plain paper. Here in Romania the acces to materials is very difficult. And here come the question: what paper do you like the most? What papers did you used during the many years of doing this? Thank you a lot

Thanks.  Since I started printing gum over ten years ago, the paper I’ve been using (and continue to use) is Rives BFK, white, 250 grams, mould-made, 100% cotton, PH neutral, 22×30.  It’s available at New York Central in Manhattan. http://www.nycentralart.com