Author Topic: Finally killed some C41 chems (Read 2127 times)

Kayos · « **on:** July 28, 2015, 10:25:57 PM »

It wasn't easy tho

22 films, including some 120, Cinevision (respooled movie stock), film acceleration twice and one film pushed 2 stops
Chems stored in airtight accordion bottles but have been subjected to severe temp changes
Last negs were a bit thin, alltho perfectly scanable, so did a leader test and nothing happened, time to mix more I think

No changes in time except the pushed film, all done at 37.8 deg c

Works out at 38p ish per film

Indofunk · « **Reply #1 on:** July 28, 2015, 10:32:59 PM »

22 is about the point that I toss the chems and mix up a new batch, even if the leader test is ok (usually it's super light by then). I still hate C41 dev and the only thing that keeps me doing it is the ~$1/roll price and the immediate delivery of dev'd negs

Terry · « **Reply #2 on:** July 29, 2015, 12:41:53 AM »

UH-OH. I just did roll #22. Time for a clip test or two.

Indofunk · « **Reply #3 on:** July 29, 2015, 03:52:41 AM »

Terry, you are magic. You can dev 200+ rolls in the same chemicals and still have them come out brilliantly.

Terry · « **Reply #4 on:** July 29, 2015, 01:24:22 PM »

I'm NOT going to take that challenge. But I think maybe there's some advantage to dividing the chemicals in half. The fact that the bottles of the second half-liter remained tightly capped (and full) while I was using the first half-liter may lengthen their useful life.

I've still got the first batch in the bottles; I'll do a clip test and see if they've got any juice left. Kayos seems to be saying that the stuff falls off the cliff (like a digital image) when it's depleted.

Francois · « **Reply #5 on:** July 29, 2015, 02:23:56 PM »

Maybe using a simple replenishing procedure would help extend its life more than we usually expect?

Kayos · « **Reply #6 on:** July 29, 2015, 02:59:32 PM »

I've been heating what I need from a 1l stock solution, according to the instructions 1 litre will do 20 ISO 400 films and 22 ISO 200 films, so I've got more than that out of the kit

Indofunk · « **Reply #7 on:** July 29, 2015, 03:22:24 PM »

Tetenal says 18 or 20 films ... either way, they're definitely underestimating so that they can more or less guarantee that number. The instructions then say something to the effect of "develop more at your own risk"

Kayos · « **Reply #8 on:** July 29, 2015, 04:32:09 PM »

As for the cliff, 21 films including experiments were fine, number 22 was very thin then a clip test showed it was dead, 10 mins at full temp and no change at all on the test piece

Terry · « **Reply #9 on:** July 29, 2015, 05:02:04 PM »

That's pretty much the definition of "falling off the cliff"! I'll try a clip test later today and report back...

Terry · « **Reply #10 on:** July 29, 2015, 08:19:58 PM »

Well. I just did that clip test on the first half-liter chems and it came out perfectly--transparent and a nice dark brown. I had switched to batch 2 after the 15th roll from the first batch, not wanting to push my luck. So, to answer Satish's challenge, I'm thinking maybe I could clear 30....

Indofunk · « **Reply #11 on:** July 29, 2015, 09:28:26 PM »

200 OR BUST

Terry · « **Reply #12 on:** July 30, 2015, 03:56:57 PM »

Wagons, Ho!

Kayos · « **Reply #13 on:** July 30, 2015, 06:21:13 PM »

Just mixed a new 1l batch, slightly annoyed I received 2 x 2.5l kits instead of 1 5l kit, as now I only have enough concentrate for 500ml without opening a new pack

It seems Terry's method of 500ml at time gets the most films, however I don't think 500 will cover a 120 film or 2 x 35 in my Patterson tank

x100art · « **Reply #14 on:** July 30, 2015, 08:36:23 PM »

I think I went 21 rolls with mine and a few of them were 120 format. I didn't see a noticeable difference.

Indofunk · « **Reply #15 on:** July 30, 2015, 08:39:52 PM »

I think I calculated that a roll of 120 has the same surface area as a roll of 135-36, so as far as the chemicals are concerned, the two formats are the same.

Francois · « **Reply #16 on:** July 30, 2015, 09:09:03 PM »

1x 35mm 36 exp. = 80 sq. inch
1x 120 = 80 sq. inch
2x 4x5 = 80 sq. inch
1x 8x10 = 80 sq. inch

see! That was easy!

Terry · « **Reply #17 on:** July 30, 2015, 09:15:21 PM »

Yeah, the Paterson tank may need more than 500ml to cover a 120 roll. I've been using a stainless steel tank , which exactly fills up with 500ml. I find it easier to handle, dipping in and out of the hot water bath, and I figure the metal tank transfers the heat from the bath to the chems more efficiently.

Kayos · « **Reply #18 on:** July 30, 2015, 09:34:23 PM »

I knew across the various formats the total area was the same, however it seems higher ISO films deplete the developer quicker

I am sticking with heating what I need then returning it to the stock accordion bottle, as I think storing it without air in the bottle is the best thing to do

Francois · « **Reply #19 on:** July 30, 2015, 10:43:25 PM »

I wonder if anyone has ever tried glass bottles with one of those wine bottle vacuum gadgets?

Indofunk · « **Reply #20 on:** July 30, 2015, 10:52:05 PM »

Quote from: Francois on July 30, 2015, 10:43:25 PM

I wonder if anyone has ever tried glass bottles with one of those wine bottle vacuum gadgets?

I believe I'm going to try this next

Also, a great excuse to buy wine!