U of S | Mailing List Archive | alt-photo-process-l | Re: tri-color gum at last , nr 2

Re: tri-color gum at last , nr 2



It might be worth noting, just for historical interest, that Demachy took up oil printing after he stopped printing gum; The Crowd is a famous oil printing of his.
kt



On Sep 24, 2008, at 10:25 AM, henk thijs wrote:

Chris,

Oh no, no GUMOIL , oilprinting is the alt-process before bromoil.
What you did with David was bromoil , in that sense that you put your neg on a bromoil photopaper (sandwich) , some 20 secs light in the darkroom, developing, fixing, tanning etc.etc.
So, you got a matrix with a non-harded photo-bromide paper, right??
OILPRINTING is a contact-procedee like gum, cyano etc..
Coating a 300grams paper -like you use for gum- with a 10% gelatine, three times, let dry and coat with a 6% potassium dichromate.
Like gum, put the neg on top , UV-light for twice the time you expose gum.
Wash out the chromate, gelatine is partly harded and now you have your matrix for oiling.
Info about the ins and outs are difficult to find; in David's book, the chapter about oilprinting is a bit thin. I had to do a lot of testing (or better: paperbasket filling with rubbish) before making oilprints ; but if you succeed there is no need for a darkroom anymore (and if you have anyway a suitable negative and some chromate ....).

Cheers,
Henk


On 24 sep 2008, at 18:46, Christina Z. Anderson wrote:


OK let me clarify: the print, below, is an oil print? OHHH not bromoil, you mean like a GUMoil? Wow is that a nice pictorial image. Her hair is so beautiful to photograph, and again your composition is really intriguing. Reminds me of Vermeer or Ghiberti.

As a segue, one of the great things about diginegs for me is that they are great for bromoil. I coldn't tell the difference between a bromoil print from a digineg and one from a reg neg because the dots of ink mask any kind of dots of the inkjet printer that might be visible with a loupe. When I was assisting David Lewis a summer ago, I was calibrating diginegs while everyone else was doing regular enlargement prints, and in the span of time they printed a couple negs I was able to print easily 10-20 separate images for bromoiling because I got my curve, color neg, and exposure time down and so it was just a matter of switching out the negative in the contact print for each separate print. And (for those who have Photoshop and understand what I am talking about) all I do is create an Action in Photoshop that does all the steps for me in one press of a button.

Back to my blurbbook.
Chris


Henk says:

On the other hand, having the negative for a monochrome gum print , i started oil-printing (i did a lot of bromoil, so the inking wasn't a big problem); see below:
http://www.thijs-foto.com/newDESIGN/JULEjan.jpg
but i must admit that this one is a lucky one; normally i have a lot of streaks of the gelatine coating (3 times a 10% gel. coating with 40x50 cm it isn't so easy working with trays).
This one was done with gelatine-tray-coating, 30x40 cm, the result is more smooth.
Cheers,
Henk