Kodak Dektol paper capacity
I looked on Kodak's website but they don't have a tech pub on Dektol.
Is there a difference in Dektol's developer capacity between FB and RC paper?
The package states 32 (8x10)/liter
First, are you talking 'working solution' or 'stock solution'? In my opinion and experimentation, Kodak is exceedingly conservative with these matters. Feel free to keep on developing as long as the true black is attainable within 90 seconds at room temp. In fact, I dilute about 1 + 4, not the 1 + 2 that Kodak recommends and I put in a little sodium carbonate to even out matters. Absoulutely no problem attaining beautiful blacks in this manner. - David Lyga
Originally Posted by David Lyga
I am talking about working solution as I just developed 70 rolls of 135 and 120 and need to make about 100 contact sheets (8x10) on RC paper. I use the cheap stuff from Freestyle Photo (Arista EDU.ultra which is $100 for 250 sheets)
What does sodium carbonate do and how much do I put in?
RC paper uses far less developer than FB, there is no absorption in the RC. There is some carry over to the stop, so you will lose approx. 1% per sheet +=. Fiber base paper absorbs quite a bit into the paper, I would replenish every 10 sheets. You only need to stop the RC for about 5-10 seconds compared to a minimum of 30 seconds with FB. I would also replenish the fixer after 25 sheets, pour off about 1/4th of the solution and add to bring the level up to where you started. I used to pull marathon DR sessions years ago, a typical session would start after returning from a shoot and end sometime the next morning.
Just use it until it stops giving the results you want. Kodak doesn't know anything about your workflow or goals.
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Oxidation in the tray is a big factor too in how much you get out of it.
I'd say if you use indicator stop bath, what it takes to ruin the stop bath 2-3 times is about what you can get out of the developer. As it fails, prints lose contrast and adjusting VC filtration will have little effect. If that's important to your contact prints, you could print an image to start and reprint it again at a midpoint or end of a session and compare contrast.
The capacity of the developer is not governed by the amount absorbed, but by the amount of silver reduced. The use of factorial development will enable you to get more sheets developed with a consistent scale.
Originally Posted by Rick A
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Kodak says 32 8x10 prints per liter. That is, of course, an average with a generous safety factor built in and assuming the most stringent of consistency requirements. This means, you can probably get a bit more out of the developer, especially if you are just making contact prints for evaluation before printing selected frames. (BTW, the capacity of developer depends on the amount of silver reduced per volume of developer, not on absorption. Carry-over affects the volume somewhat, but not a lot if you drain carefully.)
Replenishing the developer as Rick suggests will keep it working a longer time if you know you are going to be printing, say, 100s of 8x10s. It will likely use less than just tossing the developer and replacing it as capacity is reached as well. However, Dektol is pretty cheap and you could just keep a good eye on the blacks and toss it when it starts to lose activity. (I've never really had a problem with the volume of developer being reduced to a significant degree before the developer dies.)
A good way to keep track of developer activity in a situation like yours is to keep the first sheet of negatives you are contacting handy and repeat the print at Kodak's capacity (i.e., print 32) and then again at print 38, 44, 50, 54, etc. till you find the place where the developer no longer gives acceptable blacks when compared to the first print. Then is the time to toss and replace. After you have an idea of the capacity you can get, you can reduce the control tests accordingly.
Factoral development can be coupled with the above to stretch the developer even further. Note the time it takes for the image to come up in the developer and make a proportion of that with the total time. I like to use separation in mid-tones as my benchmark. For example, if it takes 20 seconds for the desired portion of the image to appear, and you develop for 120 seconds, your proportion is 20:120 or 1:6, indicating that you developed the print for six times the "emergence time." Keep an eye on this emergence time and develop your prints for six times that. After most of the capacity is used up, this time, and the resulting total time will become longer, but the overall amount of development will stay the sames and the blacks will still be good. When the blacks start to not match your test print, toss the developer and replace.
As for fixing, forget replenishing and use two-bath fixation for fiber-base prints. It is the only way to ensure adequate fixing and still be halfway economical with the fix. Mix two fresh fixing baths. Fix in the first for half the fixing time, transfer the print to bath two and fix for half the fixing time. When the published fixer capacity has been reached, toss bath one and replace it with bath two. Continue this through seven changes and then mix completely new baths.
Hope this helps a bit,
Originally Posted by David Lyga
I've never done the carbonate bit. In your usage, what is "a little"?