Gumoil

Recently I’ve become fascinated with gumoil photographic printing…  I paint in watercolour, pastel, and a little acrylic… landscapes and portraits.  I continue to improve.  I’m also intrigued about the idea of making prints, especially at home without a press.

Gumoil is an “alternative” process that combines photography with paint to make an unique image.  It is art photographer Karl Koenig’s version of a 19th Century contact printing technique.  His (expensive) trade paperback book on the subject Gumoil Photographic Printing, Revised Edition (Focal Press, 1999) is the only source, except for a few scattered mentions on the Web.  He also has a web site: http://www.gumoil.com/.

It is called “gumoil” because one major material is gum arabic and another is oil paint to bring out the image.  (I’ve begun experimenting with acrylic paint, which he also suggests as a possibility in his book.)

The process in brief is this: a mixture of a light sensitive chemical (potassium bichromate) and gum arabic is spread on watercolour paper.  (The absorbent toughness of the right watercolour paper is important.)  This is left to dry and a second coat applied if felt necessary.  A positive to the size desired is prepared.  (I do mine on ink jet transparencies, after manipulating the black and white image with Photoshop Elements.)

The positive is placed on the prepared paper, which is kept in dim light throughout.  A sheet of glass is necessary on top to press the positive against the paper.  Then either bright sunlight or UV artificial light (I’m experimenting with a photo flood lamp) is shone on the image.  The UV hardens the potassium dichromate mixed gum in the transparent areas but not in the black or darker areas.

The cooked paper is then washed in a water bath to remove any gum from the areas that will absorb paint, and left to dry. Then black paint is spread over the image and wiped off.  The black paint is absorbed in the areas where the gum is not hardened.  Then the paper is dried again. 

A bath of bleach water is used to whiten the lighter areas and to remove some of the thinner gum so a second lighter colour may be applied.

The right paper appears to be critical.  Koenig recommends 140 lb. Fabriano Artistico, of which I’ve just bought a sheet.  I’ve experimented with the acrylic paint on a variety of papers from Rives BFK to hotpressed Arches to Strathmore Aquarius II to Lanaquarelle.  The best so far is the Lanaquarelle, and I have high hopes for the Fabriano.  The Rives BFK, a printmaking paper, was the worst, much too soft, and the Arches and Aquarius II didn’t absorb darkly enough.

I’ve yet to finish the process completely and get a really good image, but it is fascinating to try.  I do the whole thing at home.  The potassium dichromate is tricky because it is toxic and requires rubber gloves and a mask to work with.  It is also a little hard to get on the West Coast of Canada.  Had to go to a chemical supply company and order some from back east. When I get a more or less successful image I will insert one here somewhere.

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17 Comments on “Gumoil”

  1. anne Says:

    I’m curious, are you using hot or cold press paper? I’m on the west coast (more inland) and heading into Van next week and wanted to pick some paper up from Opus while I’m there. I REALLY want to try this technique out but the book hasn’t arrived and beyond the information at alternative photography and a few vague references there isn’t any information on the ol’ WWW.

    Any pointers would be appreciated.

  2. fencer Says:

    I had one piece of Arches hot pressed but it didn't work very well. The paint wouldn't sink into the fibers. All the rest I tried were cold-pressed. Koenig mentions both as possible in his book. The Lanaquarelle which I think will work is cold-pressed but without much texture as is the piece of Fabriano cold-pressed I just bought.

    I haven't done much more than I mention above. I find it takes a big block of time to go at it, perhaps most of a day just to get started and concentrate on what you're doing.

    I've been working with it in the simplest way possible. I looked into mercury vapor lights (as a good UV source), contact frames, etc., but too complicated for me. My facilities are extremely limited for this kind of work! The intriguing thing is I think it can be done in a simplified way with enough trial and error…

    But the book is almost indispensable to guide you as you go along. I wouldn't recommend wasting time and material without it.

    Good luck! Let me know how your experiments go…

  3. Anne Says:

    I’ll keep you updated, it’ll be awhile though before I can do the first print – the potassium dichromate is going to take about 3-4 weeks to get to me (they must be using the pony express – heh).

  4. Anne Says:

    I was able to run off a few prints yesterday. I tried using some Lanaquarelle (140lbs cold press) and it curls when you add the gum solution but interestingly it dries flat after being processed and washed, which is a bonus. I’m not sure I like the khaki tinge in the gum and this morning did the bleach etch which whitened things up considerably. But I’m also going to try alum since I’m not sure what bleach will do to the paper in the long run – the bleaching removed so much gum, adding a second colour was next to impossible.

    It’s a lot of fun and going to try again with another paper negative. I think I over did the tonal compression a bit or maybe I didn’t expose it for long enough …

  5. fencer Says:

    Hi Anne,

    How did the ‘inking’ go with black oil paint… did you use that or something else?

    Now that the sun is out strongly, I need to have another go… I still haven’t got back to it.

    Keep me informed how it works out! There doesn’t seem to be too many people working with this method. Thanks for letting me know.

  6. Anne Says:

    I used an antique tube of lamp black oil from Stevenson’s I have from my paint kit. It’s a bit thick so used vegetable oil to help thin it out when I wiped it down after the paint had sat for a bit (less time that what the book recommends) – otherwise I would have been wiping for ages. I used cheesecloth and a stiff bristle brush meant for acrylic paint to help pull the paint up. The prints remind me of Intaglio on the Lanaquarelle paper, the black is very black, flat and there is a gritty appearance I quite like.

    I got side tracked on the gum oil and been been trying to learn how to do gum bichromates (since they use the same basic chemicals) and I think my earlier problem was I didn’t expose the print long enough for either process. I was doing them for about 6 minutes on a sunny afternoon but today I exposed one for 10 minutes* (gum bichromate) and got a better print from the overhead transparency film I’m using. Which is the other hurdle – learning how to make digital negatives … ugh.

    I found a source for powdered gum arabic (Daniel Smith in Seattle) and I’m going to order some to see if that’ll help yield a better print for rubbing. I’ve run out of the Lanaquarelle so I’m going to try another brand of paper I purchased (I got some Opus, hand made Indian paper, plus some others).

    “There doesn’t seem to be too many people working with this method.”

    I noticed that as well. Which is kinda surprises me considering that there are a lot of people doing gum bichromates – only difference between the two is the type of paint used.

    *It was bright but cloudy day out here.

  7. fencer Says:

    Hi Anne,

    Thanks for keeping in touch and keeping me informed on your gumoil progress.

    This weather is the ideal lighting condition it seems for the process. I’ve got to get back at it!

    Isn’t the gum bichromate a little more complicated (maybe not). Do you have to have a negative image or a positive like in gumoil to start?

    I printed my positives from Photoshop Elements onto inkjet mylar… that part seemed to work well.

    I got some powdered gum arabic as well for thickening… haven’t used it yet. I got it through Loomis Art Supplies… they had to order it for me.

    I’m especially interested in what paper works well for you… let me know!

    Thanks…

  8. Anne Says:

    Gum bichromates difficult? hmm … I’m leaning toward, not really. I think the hardest part is getting the pigment to gum ratio right (if you don’t the pigment is impossible to wash out). I’ve done a few and that seems to be the biggest hurdle (beyond figuring out how to get what’s on my screen too look the same as what the printer cranks out). Also I tend to jump in and not think things through and I think you need a more scientific approach to it all.

    I did a gumoil on Arches Aquarelle 140lbs CP with a positive paper negative. I mixed 1 part stock (10%) solution with 3 parts gum, double coated the paper with the solution. Then exposed the paper for 12 minutes (8 minutes didn’t seem to be enough time) at around 3:30 in full sun.

    When I washed the print I let it soak for a minute or so before I tilted the tray to run water over the print (think babbling brook rather than fast running stream). I didn’t do a full wash for 15 minutes, the print didn’t seem to need it. I then hung it to drip dry.

    The only thing I noticed with the inking in was the paper developed a few hairs from rubbing it, but didn’t seem to be anything to worry about. The paint is still wet so took a photo of the print rather than try to scan it.

    Here’s the result prior to bleaching:

    http://picasaweb.google.com/sacredcows/Gumoil

    ps: the one thing I noticed was when washing the print if you hold the paper at an angle you’ll see a bias relief of the gum which might help you decide when the paper has been washed enough or what areas need more washing.

  9. Anne Says:

    pps: need too use negatives for gum bichromates.

  10. fencer Says:

    Hi Anne,

    That’s interesting: you used a paper positive. Looking at your result, it worked really well. Was it transparent paper of some kind like onion skin, or just regular rag bond? I know the UV can probably just go through regular paper…

    I like your image of the building. The light leak just adds to it, to me. The kind of old-fashioned, textured, ambiguous quality, you get with gumoil… I just love that. You’re inspiring me here!

    Yes, when I tried it I double layered the gum as well. Hoping thickening with gum crystals will not require that.

    Have you tried the two tone method yet? (Bleach bath to get rid of some of the thinner/looser gum and apply another colour.)

    Thanks for sharing what you’re doing. Given the paucity of gumoil information, you may be providing a bit of reference source here!

  11. anne Says:

    Thanks.

    I used plain ol’ bond paper but going to try transparency film in the future to see if I can’t get sharper/more detailed prints.

    I haven’t tried the two tone method yet. That print will be a gentle reminder that, I.Can.Do.This when I screw up in the future (it’s inevitable!) and everything I did before it was so horrid I didn’t even try.

    How have your prints been working out?

  12. fencer Says:

    Hi anne,

    I got two, about letter size, that are very so-so. One turned out very streaky for some reason. Another one, an image I really like, of a knotted rope hanging off the side of a boat doesn’t have enough contrast. I will run them through the bleach bath again and see if that helps.

    I also used acrylic paint… dries very quickly, may be too. I have to buy some black and maybe sepia oil paint and give that a whirl. I’m very busy until mid-August, but hopefully I can give it another try after that.

    But the print you got is very encouraging. Keep up the good work…


  13. No no to acrylic paint. No no to Arches. Yes yes to hp fabriano artistico or cp fabriano as frequently mentioned in publications by me. Glad to see there is a blog on the subject. KPK

  14. fencer Says:

    Hi Karl,

    Thank you for your advice… and from The Source!

    My acrylic paint experiment wasn’t very successful… I will stick to oil paint. Equally my experiment with Arches didn’t pan out well. I did get a sheet of Fabriano CP. I need to give gumoil another shot this summer with the sunny weather.

    It’s too bad that Anne’s example above has disappeared… it turned out quite well, and you might have found it interesting. Perhaps she will reappear.

    Thanks again for coming by.

    Regards

  15. karl koenig Says:

    I am thinking of having a small workshop on gumoil in my studio, here in Albuquerque. It would take three consecutive days. Cost will depend on enrollment. Easier if I supply paper, chemistry and pigments as I know what works. Say, January or February. Write me if interested and I will respond. Use Gumoil Workshop as subject in emails.

  16. fencer Says:

    Hi Karl,

    Thanks for the announcement and the sites… Wish I was in Albuquerque.

    Regards


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