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  1. #11

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    Quote Originally Posted by paxette
    I'm just learning how to do this as well and I succeeded in doing a horrid but recognizable print. I've been doing pretty much what everyone else has and getting pretty much the same result. I tried using some Aquarello 230gsm CP rough and didn't like what I saw and found Lanaquarelle 140lbs CP to be more promising. I think my problem is the negatives or not enough gum.

    Wish I could help but I'm still fumbling along.

    I think one key issue could be the gum rather than the paper (as long it is high quality cotton based).

    Mr Koenig in his book says that gum below 14 baume degrees might produce too thin results. And suggests to use powdered gum to be mixed by yourself, instead of ready made gum. By the way he also says that Windsor and Newton should be ok and that's the one I used so far. I tried double coating too, without any change in the result. I used both digital positives and real film positives with the same, awful, results.

    I'm wondering perhaps I could mix the gum with some albumen as described in the temperaprint process (it's a process similar to gum bichromate that uses acrylics instead of oil paints, check alternativephotography website for info). That could make the gum substrate thiker, but might cause new problems as well ...

    I also wrote to Mr Koenig, but I didn't get any answer yet. Does he actually post somewhere in places like APUG?

    cheers

  2. #12
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    Fulvio, I think it might have been the exposure time in my case.

    The book recommends around 6 minutes (which I've done before) but today I did 4 prints, two single coated and two double coated. Two were exposed for 8 minutes and two for 12. I based it on the exposure times people have used to develop cyanotypes found on alternativephotography.com. I'm north of Arizona so I figured I should adjust my exposure times to compensate.

    My transparency doesn't work at all, it's far too flat and the 12 minute exposure was impossible to clear (I still have dichromate stain in the gum). But the paper negative exposed for 12 minutes yeilded an excellent negative - my best thus far. I'm going to try a single coated gum tommorow at the same time for 12 minutes to see how much of a difference there is.

    I'm using ready mixed gum (14 degree baume) but I'm going to order some powdered gum if this print fails once I've inked it up and done that part of the process.

    Least I know I'm now heading in the right direction (I think or is that hope?)

    ps:

    "1) Got a 5% potassium bichromate solution, mixed 1:3 with gum arabic."

    This is just a guess but the book says to use a 10% solution which might be why nothing is working for you.

  3. #13

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    Quote Originally Posted by paxette
    The book recommends around 6 minutes (which I've done before) but today I did 4 prints, two single coated and two double coated. Two were exposed for 8 minutes and two for 12. I based it on the exposure times people have used to develop cyanotypes found on alternativephotography.com. I'm north of Arizona so I figured I should adjust my exposure times to compensate.
    I do all my exposures with a UV printing box I made myself. With cyanotypes, oilprints and saltprints works great. Once I tried also photopolymergravure with a friend and it's also fine. It does the job also with gumoil... The fact is that right after exposure the "negative" on the paper looks great: a lot of tones and details... But then, when I wash it most of the prints i gone along with the gum arabic. If I prolong exposure times it doesn't change much, in the end I still got a crappy print.

    "1) Got a 5% potassium bichromate solution, mixed 1:3 with gum arabic."

    This is just a guess but the book says to use a 10% solution which might be why nothing is working for you.
    Mmmm... I don't think so. The book is a little bit confusing (like in many other parts). In the chapter about paper & coating it says to prepare a saturated solution of potassium bichromate. But then says that it is a stock solution. In the end of the book there's a quick list of what do to for producing gumoils and it's clearly written "5%". By the way I was confused in the beginning too... Because he talked about this saturated potassium bichromate solution... Then I read the end of the book and got even more confused. So I tried with both 5% and 10%, but this detail doesn't solve my problem, it affects only exposure time. I believe that 5% is the correct amount indicated by the author.

    bye

  4. #14

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    gumoil

    I just purchased the book, but after reading your posts I'm not sure where to start! Has anyone here yet produced a decent print?

    HMR

  5. #15
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    Quote Originally Posted by paxette
    I'm just learning how to do this as well and I succeeded in doing a horrid but recognizable print. I've been doing pretty much what everyone else has and getting pretty much the same result. I tried using some Aquarello 230gsm CP rough and didn't like what I saw and found Lanaquarelle 140lbs CP to be more promising. I think my problem is the negatives or not enough gum.

    Wish I could help but I'm still fumbling along.
    FWIW, I just received this e-mail from Karl a day or two ago.

    I am sending this to you as one who has indicated an interest in learning the gumoil print-making process in a workshop setting. I plan to have two workshops in Albuquerque at my 121 Wellesley Ave SE studio. The two separate shops will take two days over two different weekends. Workshop #1 will be held on Saturday and Sunday October 7 and 8. Workshop #2 will be held on Saturday and Sunday October 21 and 22. If neither of these dates is convenient for you, let me know and I will consider offering a further date later on in the year. For the moment, however, these are what I will have on offer. The cost will be 600.00 per person and I will supply materials, oils, paper, etc.


    The maximum enrollment per workshop is 5 people. The minimum is 4 people. If I do not have a guaranteed (i.e., pre-paid) 4 enrollees, the workshop will be cancelled. The sooner you send me a check and guarantee a place the quicker I can let you know if the workshop will be held.




    There are plenty of motels within easy walking or driving distance and lots of restaurants nearby in the Nob Hill district. The University of New Mexico is not far away, either.


    You will need to prepare a transparency (at least one) in b/w of the size image you want to print in gumoil and bring that with you. The maximum size paper I will supply is 11x15 inches so your transparency will need to be smaller than this. I will send more info to those who register by sending me a check.


    [size=+1]Make your check payable to Karl P. Koenig and mail it to me at: 6435 Nabor Road NW, Albuquerque, NM, 87107. Phone 5053444429.[/size]


    It would be helpful if you have my book "Gumoil Photographic Printing" published by Focal Press, Boston and available through all major book sellers. There is a first edition in 1994 (no computer info) and a revised edition in 1999 (which covers making interpositive transparencies on the computer). Either one would be helpful to you. I can send a more complete biblio of various articles, etc. on request.


    Sincerely, Karl


    PS Let me know if you want off this mailing list
    Don Bryant

  6. #16

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    Quote Originally Posted by hmr28
    I just purchased the book, but after reading your posts I'm not sure where to start! Has anyone here yet produced a decent print?

    HMR

    I tried, but did not succeed.

    I tried with both 5% and 10% potassium dichromate sensitizing.

    I tried with windsor & newton gum and also with self made gum solution (alone or mixed as a thickener with the windsor & newton one).

    I tried several kinds of paper: Fabriano F5, Fabriano Artistico, Schoelleshammer and some other I don't remember...

    Yes, the principle works: potassium dichromate hardens the gum that becomes impossible to remove with water. But I have almost no midtones. Just black and white, the contrast is extremely high. The midtone areas are messed up with a lot of random pigment. I also made a special digital negative using a rasterization effect (there was only pure blacks and whites in it, in order to produce an halftone image), but that did not make a huge difference.

    Frankly I do not know what is wrong. I'm sure I've read the book correctly. The book is poorly made, not really technical compared to others, lacks of a troubleshooting chapter/section, sometimes contradicts itself or makes confusion (like when it says to prepare the dichromate solutions, it says to make a saturated stock potassium dichromate solution, then later in the appendix says to use a 5% working solution). The book is also very expensive, compared to other alt.photo books, it's economically printed and there are only few full color images inside.

    I wrote Mr Koenig a short email asking him some informations, but he never replied. I'm sure he would have replied if I were offering him money to buy another book or ask for joining one of his workshop...

  7. #17
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    Thanks donbga but I raided the piggy bank in order to get the supplies to try my hand at this.

    I've completed one half decent print (successful enough that I'm not cursing Koenigs name)

    I double coated the gum mixture on Arches Aquarella using a paper negative (which I compressed slightly in PS before printing) then exposed for 6 minutes mid afternoon under clear sky's. I didn't bleach the print afterwards or do anything else to it, it's my "I can do this" example when I get discouraged - heh.

    I'm finding that choosing the right negative is really important since every other attempt I've made has yielded duds.

  8. #18
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    Quote Originally Posted by Fulvio

    I can't find powdered arabic gum at the moment. But I have some gelatin here. Should I try using gelatin instead of arabic gum? If nobody else is using gelatin for gum bichromate or gumoils there must be a reason, though...

    Anyone else has some suggestion?
    http://www.lawrence.co.uk/ sell 500gm for £6.94 plus delivery. If they won't ship to you, drop me a pm and I'll buy it and send it on to you.

    J
    ~John~
    --------------------------
    www.johnbrewerphotography.com
    There are 10 types of people in this world - those who understand binary and those who don't.

  9. #19

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    Quote Originally Posted by paxette
    Thanks donbga but I raided the piggy bank in order to get the supplies to try my hand at this.

    I've completed one half decent print (successful enough that I'm not cursing Koenigs name)

    I double coated the gum mixture on Arches Aquarella using a paper negative (which I compressed slightly in PS before printing) then exposed for 6 minutes mid afternoon under clear sky's. I didn't bleach the print afterwards or do anything else to it, it's my "I can do this" example when I get discouraged - heh.

    I'm finding that choosing the right negative is really important since every other attempt I've made has yielded duds.

    I think it is a good picture.

    How did you wash/develop the hardened (exposed) gum?

    Also, what do you mean paper negative? Do you mean a print from the darkroom or by computer or it is a digital negative on trasparency?

    Which kind/brand of oil color did you use?

    Forgive me for all these questions, but I've tried hard at this process and my best picture wasn't close to yours at all...

    cheers

  10. #20
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    I think it is a good picture.
    Thanks.

    How did you wash/develop the hardened (exposed) gum?
    I let it sit in the bath water until the dichromate leeched into the water. Then I had water slowly trickle into the tray until the dichromate cleared which I found took less time to happen than what Karl suggests. I didn't hose the image down after the dichromate cleared either, I'm finding even with a double coat of the gum mixture it's still a tad thin (I'm laying it on quite thickly) and the gum washes away easily. The other thing I noticed is, if you tilt the paper you'll see a bias relief of the image which helps to determine if you need to wash it some more or have gone too far.

    Also, what do you mean paper negative? Do you mean a print from the darkroom or by computer or it is a digital negative on transparency?
    It's a digital negative (actually a positive on paper) printed on cheap office paper with a ink jet printer. I've tried transparency film but thus far all the gumoil prints from those transparencies have been duds. I know next to nothing about making digital prints so I'm kinda winging it while I learn.

    Which kind/brand of oil color did you use?
    I had an ancient tube of Van Gogh, Ivory Black kicking around so I used that.

    Forgive me for all these questions, but I've tried hard at this process and my best picture wasn't close to yours at all...
    No problem

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