paul_verizz

This is amazing, an almost new thread about DK-50! In 2015 for reasons I don't remember, I decided to make and try DK-50 on Plus-X 1:1. I was beyond blown away! What grain there was, minimal and tight. Nothing like one would expect in theory. Great tonality. Where have you been for the last 65 years? At the time I was very much involved with APUG, which I see has rebranded itself. I did some posts there which you may find of interest. Anyway, about then I had to move and here it is 2019, ready to get back to film and developing. So I've been going through all my records and notes and internet searching as I get ready to go down the rabbit hole again. Elliot, you observations about being equal to T-Max times will be a life saver. Development times has been the bottleneck for DK-50, for sure. I have printed out the pages from the Massive Development Chart filtered for DK-50, and all films for T-Max developers. BTW, that motorcycle image is stunning, right on what I got with my short lived experiments. I also started experimenting with DK-50 in a divided format; god, I've been a slave to the idea of divided development for 40 years. My original post on APUG: DK-50, Still alive and well?

<p>Where I missed the boat WAS in the math. Maybe my reading comprehension? A lot of developer and other threads aren't the best written, although Patrick Gainer's tend to be good. And then with every tweak someone wants to use, or the dilution rate, the details get lost, like that old campfire game of telephone.<br> Reading back through my saved pages again, I realized that the 5g carbonate added in Gainer's PC-Glycol was after being diluted to the equivalent of 1:3 Xtol. Looking back at my chart in Haist, it became obvious that I would need about 40g of Kodalk for an equivalent pH.<br> I took 50ml of my working strength PC-K, but with the 5.1 pH, added the equivalent of that 40g/liter, and got a pH of 9.8! More importantly, my daylight test snippet of TMX is developing well.<br> Yes, I know how sodium metaborate is derived. Personally, I'd rather just take it from a jar.<br> I also noticed that Xtol has a high level of sodium sulfite, so there is already quite a bit of alkalinity to counteract the sodium ascorbate even before the metaborate is added.<br> Thanks for the feedback, peter!</p>

<p>@Peter, I thank you for taking the time to respond. I know what is theoretically needed, which is why I'm alarmed at such a low pH. I've gone over the mixing math several times, admittedly not my forte, but I think I'm good in that department. <br> I've no concern about minerals because A) they aren't in my tap water here, and B) I need to solve the pH issue first. I might just start over, it's all cheap enough. </p>

<p>About two years ago I was going to take the ascorbic acid developer plunge. I collected quite a few intertube pages and kept them. Also around that time I mixed up a PC/water concentrate, using the classic 1:40 ratio of Phenidone to Ascorbic Acid. I tossed it into my freezer and forgot about it. <br> <br />Fast forward, got tired of everyone with $1K and a digital camera is now a "photographer." ("What's an f/stop?") Got my old Ricoh's fired up, took film out of the frozen and lead lined vault, and am now shooting for test color neg which I'll process, and conventional B&W. <br> I thawed out my PC concentrate and tested the pH, 3.1. (Digital meter, zero'd with pH 7.0 calibrating lab water.) I put 60ml of that into the beaker, so now I have .15g Phenidone and 6g ascorbic acid. I decided to go with 4.5g Kodalk for the alkali. I came up with this from Michael Madio' experience with 18g borax, using my extensive references to equate about 4:1 borax:Kodalk for an equivalent pH.<br> The pH is only 5.1! <br> Gainer suggests 5g sodium carbonate, that should, again per above Haist reference, less than a 2:1 difference from Kodalk. Yes, I understand that's significant, but since I'm only at pH5.1, I don't even see an over ph7 on the horizon! And these matters are not linear.<br> So, does ascorbic acid work at a much lower pH? I've seen no reference to pH of the developers. Xtol uses a reasonable quantity of Kodalk. Am I missing something? <br> FWIW, the Haist reference refers to research that shows equivalent densities from 1 unit of sodium hydroxide, 3 of sodium carbonate, 5 of Kodalk, or 20 or borax.<br> Sure, I'll try a test strip in daylight, but I thought I'd shout out.</p> <p> </p>