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View Full Version : Unit to print paper negs. on carbon tissue



blindpig
04-04-2015, 02:45 PM
I've wanted to make carbon prints for a while now and built an 11X14 camera toward that end.The problem is I've also fallen in love with paper negatives and would like to print them on carbon tissue soooo,knowing of some of my crazy exploits you won't be surprised that I've just finished a piece of equipment which(if it works)will allow paper negatives to be projected onto carbon tissue.I'll take some pictures when the paint dries.
Like most of the experimental stuff I build it's made from materials I had at hand and therefore ain't that good looking but since it might not work why spend money to make it pretty? Yesterday I sent an order for carbon tissue,sensitizer and clearing agent to Bostick and Sullivan so tests can't be far behind
More to come.....

Tom Persinger
04-04-2015, 09:23 PM
looking forward to seeing both your results as well as the contraption you've constructed! Thanks for the update!

blindpig
04-05-2015, 11:51 AM
Thanks Tom,
Just thought of another change to make the contraption a little more versatile so will hold off on pictures a little longer.The results will be up in the air as I haven't ever made carbon prints and am attempting projecting paper negatives onto the tissue(a lot of variables)but think it will be fun.If this doesn't work the gadget will be turned into a contact printer and I'll resort to shooting litho film in the 11X14 camera for carbon prints.

Ned.Lewis
04-05-2015, 12:35 PM
I've never made a carbon print. So far the dichromates keep me away from this process and gum. But isn't it possible to contact print a paper negative?

Tom Persinger
04-06-2015, 08:19 AM
Definitely possible to contact print paper negs (especially if waxed). The only issue might be that the exposure times would be longer than a film negative. I'm not sure how long a projected exposure would be, but I suspect long... looking forward to seeing more!

earlj
04-06-2015, 01:18 PM
Carbon tissue exposures are similar to other uv-sensitive contact processes (cyanotype, pt/pd, kallitype, etc.) so you could test your projector and negatives with another process. Carbon prints are not like anything else, so you might want to work out the procedures for making a print with a contact negative and uv light source before you try your hand at the projected version.

blindpig
04-06-2015, 03:23 PM
Sounds like a good idea Earl, it would require removing the lamps and re configuring the set up and I may end up doing that but will probably give'er a try in the present configuration first(remember"Even a blind pig finds an acorn once in a while"),will probably live to regret it but what the heck!
I made a few pictures of the unit and must warn you once again it's made of odds and ends and looks it.

http://i820.photobucket.com/albums/zz128/blindpigetc/8fcf5db9-6424-414d-becb-72f3f9f1a469_zpsrb4mfezo.jpg (http://s820.photobucket.com/user/blindpigetc/media/8fcf5db9-6424-414d-becb-72f3f9f1a469_zpsrb4mfezo.jpg.html)

http://i820.photobucket.com/albums/zz128/blindpigetc/8bdcd1f7-7f8a-4d1d-9377-5f6e7ae0d78b_zpsepjdmuya.jpg (http://s820.photobucket.com/user/blindpigetc/media/8bdcd1f7-7f8a-4d1d-9377-5f6e7ae0d78b_zpsepjdmuya.jpg.html)

http://i820.photobucket.com/albums/zz128/blindpigetc/4d0a39ae-7f9b-4142-83f7-1ca97ef20c4a_zpsvizg09hf.jpg (http://s820.photobucket.com/user/blindpigetc/media/4d0a39ae-7f9b-4142-83f7-1ca97ef20c4a_zpsvizg09hf.jpg.html)

http://i820.photobucket.com/albums/zz128/blindpigetc/2469cd12-4c0a-4da1-8fa7-356c0b5bc051_zpsmdz39msa.jpg (http://s820.photobucket.com/user/blindpigetc/media/2469cd12-4c0a-4da1-8fa7-356c0b5bc051_zpsmdz39msa.jpg.html)

This camera backs up to the door of my little dark room for operating it in dark.
More to come.
Don

blindpig
04-06-2015, 03:53 PM
Should add a little explanation as to the operation of the copy camera/enlarger.
The hand wheel in the last photo moves the copy board/light unit back and forth for focusing and the easel moves up and down for sizing. The image being copied passes from the copy board through the lens reflects off a 45 degree first surface mirror and down to the easel,bending the image path allows a physically smaller unit and also inverts the image eliminating the need for a double transfer normally required for a right reading carbon print. The "boxes" on the back door serve two purposes, the smaller one is for handwheel clearance and the larger is a light trap to allow free air passage inside the unit. With the easel in it's up position I can hang sensitized tissues to dry as it's the largest dark box I have.
Hope this helps...
Don

JoeVanCleave
04-06-2015, 04:13 PM
Very ingenious, thanks Don for sharing this. I'm thinking eventually it'd be nice to replace the head on my Besseler 4x5 with an opaque projection head.

~Joe

banana_legs
04-07-2015, 04:40 PM
Wow, looks really fun!

I second Earl's suggestions to try something like cyanotype first in the enlarger, and try to get carbon working with negative on film and a UV source first; it took me a dozen or so attempts to get a basic carbon transfer to work even with a film negative and a UV box.

To give you a rough feel for times, my carbon exposures with a 4% potassium dichromate solution are about twice as long as for traditional cyanotype . With a digital negative (on clear acetate) in my UV box (4 x 15w UV tubes, sensitised paper 2" away), a cyanotype takes about 3 minutes, carbon about 6 minutes to expose. Gum is faster than cyanotype and casein faster still, although you will need multiple layers to get a decent tonal range.

Good luck!

Evan

blindpig
04-08-2015, 02:10 PM
My intention is to test with a pre-made grey scale 8X10 or so in size.it would have approximately 9 steps from black to white each about 1/2 or twice the exposure of the next step,these steps would be horizontal on the paper.Then put vertical black borders an inch or so apart and expose the tissue to each vertical 1 inch wide strip at a increasingly longer exposures. Hopefully resulting in an approximate exposure time.My thinking is the black dividing borders would keep the grossly under exposed strips from lifting the adjacent strips with more exposure when developing and transfering.May have to try this more than once I expect with longer exposures but should eventually arrive at a desirable exposure(if this gadget works).Still waiting for the tissue and all to arrive,wish me luck...
Don

blindpig
04-14-2015, 12:56 PM
Just now received my package from Bostick and Sullivan and am getting pretty excited.Have to make the step scale mentioned in last post and off to testing!
Am hoping that using their professionally made tissue and clearing some print paper for the receiver sheet will eliminate some variables and afford a good result without using up all the materials. I have 12 SQ feet of tissue, 30 Gr. of Potassium Dichromate and 100 Gr.Sodium Metabisulfite,enough for a start don't ya think?
Don

earlj
04-17-2015, 02:52 PM
Good luck, Don. PM me if you get into trouble with the sensitization, development, and transfer of the carbon tissue. Soon we will have you ordering gelatin to make your own glop . . . . .

blindpig
04-20-2015, 02:56 PM
Well. test#1 TOTAL FAIL! can't say I wasn't expecting something like this.My 15" lens has a coating and evidently it's very good'cause after stepping exposures from 5 minutes to 40 minutes there wasn't even the slightest evidence of density on the receiver sheet and not showing on the tissue either.The only next likely lens I have is a uncoated 10" projection lens I just found in my stash soooo only a slight delay for adapting this lens and on to test#2.
Disappointed but undaunted,more to come.
Don

blindpig
04-22-2015, 06:05 PM
OK! test #2 FAIL! I adapted the 10" uncoated lens and tried second test. Thinking one of the problems could be my sensitizer mixture and/or temperatures(or lots of other things)I decided to try contact printing my mixtures etc.by darkening my shop and exposing an 20 step film negative step wedge in contact with the tissue in the copy board directly in front of the lights.The result is a 3 step carbon print with areas not covered yielding a dark gray not total black as hoped. The lights are two 400 watt metal halide about 12" from the copy board,exposed for 6 minutes.The sensitizer is a 3% solution of potassium dichromate,spirit coated on the tissue.
My best guess is the percentage of dichromate needs to be lower to increase contrast (or not) so guess that's next. Any and all suggestions will be appreciated.
Don

blindpig
04-23-2015, 09:40 AM
OH! Guess I forgot to mention I'll be increasing the exposure a lot. May need more light like a couple of 1000 or 1500 watt halides,we'll see.

earlj
04-23-2015, 10:33 AM
Don -
Have you used your exposure unit for another process? Can you print a cyanotype with it?
The carbon process has a very long scale - you should get more than half the steps of your 20 step wedge if everything is working right. It sounds like you are not getting enough exposure.
What is the temperature of the water for your mating bath? What is the temperature of your development bath? Was the tissue backing easy to peel?

banana_legs
04-23-2015, 04:02 PM
Hi Don,

Yes decreasing the sensitiser concentration will increase the contrast, but it will also mean you need to increase the exposure to get the same base black. The rough guide I use (not precise by any means, but is usually close) is that halving the sensitiser concentration will need double the exposure to get the base black back, and will shorten the scale by 3 steps on a 21 step wedge (i.e. 3 half stop steps). Reducing the distance from the lamp to the print will reduce the exposure times quite quickly (it is a square law, so 1/2 the height will reduce time by 2 stops), but there is a risk of uneven illumination if you get too close.

As Earl says, it sounds like a much longer exposure (or similar with brighter lamps) with the 3% solution may be a better place to start to get a decent black, followed by a reasonable number of steps with tones. Increasing the sensitiser concentration will improve the black level for the same print time and also give you more tones. The other issue for losing density is when the image is difficult to wash with lots of bits of undissolved tissue remaining for a while after the peel; if that was the case, the print could have stayed too long in the developing water and resulted in a loss of pigment (the solution in that case is usually to soak the tissue longer in the mating to absorb more water into the gelatine before developing). My prints take between 5 to 10 minutes maximum to develop, with only a minimal amount of 'jiggling' in the water.

I did do some printing with very low concentrations of dichromate (down to 0.5%) and in front of a bank of UV tubes, some of the prints needed over an hour exposure.

Best regards,

Evan

blindpig
04-24-2015, 11:06 AM
Earl,the temp of mating bath was 60 F and dev bath was 103 F, the tissue separated easily and I agree more exposure is necessary along with some physical changes to the equipment to aid the exposure.The development time was 5 minutes soak then peel and about 6 or 8 minutes more soaking with an occasional jiggle and the water draining from print was clear.
Evan,I'm going to move the lamps closer it will require some "creative"engineering but think some change is possible.Talked to my son last night and he is in the process of acquiring some Halide lamps being removed from a large commercial building and will check the possibility of some being 1000 or 1500 watts (luck may be with me).Presently am going to stay with 3% sensitizer solution and lengthen exposure time,may increase sensitizer percentage later to help shorten exposure time as well.
Thanks you guys for the help,please keep it coming.
Don

blindpig
04-24-2015, 11:17 AM
Earl, sorry I didn't answer about other processes with this set up.No I haven't tried any other processes except shooting paper negatives in-camera which doesn't qualify as another process technically.Carbon printing and paper negatives are all I'm into right now and being conservative (read cheap) is about all I can afford to invest in financially and mentally so far.
Thanks again for the help,
Don

earlj
04-24-2015, 01:35 PM
I was just trying to ascertain if your exposure lamp was giving enough intensity in the right wavelengths. Sounds like your water processes are good, so work on the exposure, and you should start to see some success. Carbon printing seems like such a simple process, but there are a lot of variables that affect the outcome, so it takes some repetitions to get a good workflow. Keep us informed on your progress.

blindpig
04-24-2015, 02:39 PM
Thanks Earl,
I've heard from my son and he is expecting the lamps tonite so am thinking of testing exposures with set up as is and extending time till something shows up. If the lamps he's expecting aren't any more powerful than mine I can move the lights in toward center and forward toward copy board a total of about 6 inches,which is about 1/3 closer to the negative as it is presently(not much but every little bit will help).However if he receives 1000 to 1500 watters I'll leave the physical structure alone(just change lamps).

blindpig
04-27-2015, 06:06 PM
Today tried looooong exposures through the lens/mirror and still no luck.One exposure was two hours long(whew!).My best option is if this guy my son has bringing him some lights(somehow he hasn't shown up yet,but son says he will)and they are 1000 or 1500 watt lights.I also need to check my bulbs as they came from an auditorium I suspect they aren't the type with high Kelvin temperature like the one's used as grow lights in a green house.Those bulbs may be a my only other option and I don't know if that will even help.Don't think at this point moving lights a little closer to the copy board will be worth the effort either.Pretty disappointing, but if all else fails I can turn the unit into a contact printer and familiarize myself with shooting litho or X-Ray film in my 11X14 camera,still allowing me to contact carbon prints(so all won't be lost).
Don

blindpig
04-30-2015, 01:20 PM
After some thought. First,I've decided until another light source can be obtained that a rail with a second easel will be attached in the back of the unit and an access opening cut in the upper part of the back to allow projecting from the copy board through the lens onto the new easel location. This will let me print my paper negatives larger than 4X5 (which the reflective enlarger already does).Second ,by exchanging one of the tubular light reflectors for the original parabolic reflectors and having a vacuum printing frame directly below it I can contact print carbon tissue. All this will let me use the unit and still have it intact for possibly later projecting paper negatives on to carbon tissue(hate to give up!).
In the ongoing search for powerful UV lights have discovered Metal Halide aquarium bulbs at 400 watts and 20,000 K,wonder if these would produce more UV that my current bulbs,certainly are more blue.The quest will continue.
any thoughts will be appreciated.
Don

blindpig
05-21-2015, 03:32 PM
Finally finished the alterations to the unit.Since prospects for getting larger light sources in the near future aren't good,I've altered the unit to get some use from it it the meantime.First I cut an opening in the back to allow an image from the copy board through to the new projection back.This will allow printing 8X10 and 11X14 paper negatives reflectively. Second by exchanging the tubular light reflector from one of the lights for it's original parabolic reflector and positioning it over a vacuum easel I can contact carbon prints. No sense having the unit setting around taking up space when it could be of use.Here are some pictures.
http://i820.photobucket.com/albums/zz128/blindpigetc/ba121fbf-c383-4ab0-9d4b-9a51b42e08e7_zpssmo0ztos.jpg (http://s820.photobucket.com/user/blindpigetc/media/ba121fbf-c383-4ab0-9d4b-9a51b42e08e7_zpssmo0ztos.jpg.html)
http://i820.photobucket.com/albums/zz128/blindpigetc/contact%20printer_zpsckcrs4wc.jpg (http://s820.photobucket.com/user/blindpigetc/media/contact%20printer_zpsckcrs4wc.jpg.html)
Onward!!