Quick carbon printing question re exposure

[andreios]

Hello,
after long time of dreaming and hesitation I have started. The day before yesterday I have poured my first tissues, I have sensitized them a while ago now I am waiting until they dry.
However - somehow despite reading quite a lot here and elsewhere I have no idea where to start with the exposure. Any ideas? I am using facial tanning lamp.
Could you share your exposure times - or relations to other processes like cyanotype od van dyke? As I said, I understand that I have to fine tune my own times but I just need an idea where to start.

Thanks a lot!

Andrej

[sanking]

Hi Andrej,

First, congratulations on living your dreams and actually making carbon tissue. And I wish you continued success in the future with your printing.

Exposure times are highly dependent the nature of your tissue. Thin, heavily pigmented tissues print faster than thick, lightly pigmented tissue. However, is your tissue is on the normal side for hand-made tissue, say about pigment loading of 1.5%, your exposure times should be similar to those of vandyke and pt/pd, shorter than cyanotype.

I have no experience with facial tanning units, buy my exposures with Black Light fluorescent tubes used at about four inches from the printing frame are about 20 minutes in length with step wedge negatives (Stouffers, for example) and well exposed and developed B&W negatives.

Sandy

[mdm]

Good luck. Dont worry if your first exposure is too long or too short because you can only learn from the experience.

[andreios]

Thank you all, especially Sandy - this is just the startpoint I needed..
Can't wait to get home to try! )

[andreios]

May I put another question in the same thread...

As a father of family with 3 children (and that is small children, the eldest just a bit over 3 y/o) my time for darkroom is a bit limited, but more than that is highly irregular and unpredictable. So I was wondering the other day:

How long can store the glop in a container and it would be stil useable?

How quickly after the tissue has dried shall I sensitize it?

And how long is it OK for the sensitized tissue to hang/lay before it is exposed and transfered?


Thank you.

[mdm]

The glop can be refrigerated, and you can add thymol to stop it going mouldy, but I have always poured a whole batch at a time and put the dry tissue in the freezer until use. It keeps a long time in the freezer and even out of it, to test if tissue is ok try some unsensitised tissue in warm water, if the glop dissolves away from the support it should be ok to use. Sensitised tissue should be used as soon as it is dry because of the dark effect which changes its characteristics over time, but some people sensitise a whole batch at a time and freeze it until use, which is not a bad idea really, to speed up your workflow.

[CP Goerz]

'How long can store the glop in a container and it would be stil useable? '


In the fridge....about two weeks max, it can be frozen and defrosted if you plan on longer times but fresh is best.

'How quickly after the tissue has dried shall I sensitize it? '


Depends on the pigment, some start to harden the gelatine and will give a foggy appearance after a week, additionally the gelatine becomes more difficult to dissolve and often the base support will tear off the image in development. Fresh is best(use withing three days).

'And how long is it OK for the sensitized tissue to hang/lay before it is exposed and transfered?'


At the most three days, best performance will be sensitizing the night before and using it the next morning/afternoon. Once the sheet is sensitized fog will start building up after a day.

[CP Goerz]

'However - somehow despite reading quite a lot here and elsewhere I have no idea where to start with the exposure. Any ideas? I am using facial tanning lamp.'


You can always do what Ansel did with silver prints by gradually covering the sensitized tissue during exposure, say every 4 mins you scoot a sheet of cardboard further over so when you develop the image you can gauge which 'test strip' looks best.

[Vaughn]

As a father of family with 3 children (and that is small children, the eldest just a bit over 3 y/o) my time for darkroom is a bit limited, but more than that is highly irregular and unpredictable. So I was wondering the other day:

How long can store the glop in a container and it would be stil useable?

How quickly after the tissue has dried shall I sensitize it?

And how long is it OK for the sensitized tissue to hang/lay before it is exposed and transfered?

Hello! I am also a father to three children (triplets), but they are 15 years old now. I gave up the idea of using the 8x10 for awhile, and having no time to do any processing, I used a Polaroid SX-70 camera a lot until the boys started to crawl...it was all I had time for, and once they started crawling, I could not pose them any more! Its like sweeping ants -- you can get them in a pile, but they don't stay that way. I had been doing carbon for several years prior to the boys' birth, but after things mellowed out a little with the boys, I taught myself platinum printing...thinking it would be a little faster process than carbon. I use both processes now -- including an ongoing series of my boys in the landscape.

I have had mini-disasters with glop in the fridge (no preservative was used -- it would have helped)...I prefer to make the glop and pour that same day. I typically start a batch of glop in the morning and have it sit in warm water for up to 12 hours (usually closer to 8hrs) before I have time to pour the tissues that evening. I have also made a batch of glop in the evening, kept it in the warm water bath, and poured tissues in the cool quiet of the early morning. This also gives the bubbles in the glop plenty of time to remove themselves.

How much time I have to pour that evening determines how much glop I make in the morning. One 'batch' of my glop makes about 850ml (90 gm gelatin and 750 ml water) -- I'll make two to three batches at a time. For an 8x10 negative (9x11 tissue) I pour 120ml of glop. If you have the space, one can speed up the pouring process by pouring large tissues (to be cut up after drying) or pouring two to four smaller tissues at a time.

I give freshly-poured tissues 6 or more hours drying time with a fan, usually no more than 12hrs. Getting the surface of the tissue dried quickly has kept the mold away here where I live (cool and humid). I wait a total of 48 hours before using the tissue. My tissue is relatively thick, so thinner tissue and/or drier climates would not require as much time to dry.

I have kept the tissue out in the open for up to a couple months before using it without any significant difference (fresh tissue does seem to melt a little easier, but the results are the same). Also -- I use lampblack watercolor pigment which seems to be very compatible with the gelatin. Since the watercolor pigment is in a carrier of gum arabic, the manufactures most likely avoids any chemicals that might cause the gum to harden.

I routinely have used sensitized tissues 8 to 10 hours after drying. I spirit sensitize all the tissues I plan on using that printing session, then I hang the tissues in a dark room with a fan for two hours. Then I put them in a box and spend the next 8 to 10 hours exposing and processing them. There is probably some increase in printing speed over that period of time, but I am use to it and it has become part of my system.

I once waited 12 hours to develop a mated tissue -- that was tough! Finally got it separated and I used 120F water from a hose to sort of sandblast the unexposed gelatin off the print. Fortunately the hardened (exposed) gelatin was still harder than the time-hardened unexposed gelatin! I got a print, but I do not recommend waiting to develop more than a few hours after transferring the tissue to the final support.

Good luck in your printing -- and in your adventures as a dad!

Vaughn

[andreios]

CP Goerz - thank you very much for your precious practical advice - I will keep that in my mind and try to plan - to anticipate the dilemma of Friday night - stay in the darkroom till' early hours or go to bed and leave the house before light to get some images...

Vaughn, thank you so much for sharing your experience. Much appreciated. And thank you even more for sharing your workflow. I am going to re-read it and try to get some inspiration for my own.
Best of luck to you and your boys!
Andrej