C41 control strips, anyone??
I've started my first color project. It will be (is being) shot on Portra 400NC 4x5 sheets. The problem is the processing. The best I can find costs me about $4 per sheet. I've looked at mail order as well (Sammy's Camera), but shipping cost brings the price right up to the local price, and the turnaround is 2 weeks at least. Locally, I get the sheets processed the same day.
I've looked at buying the Kodak Chemistry and processing the sheets myself. I have a Jobo ATL 2+, the chemistry is readily available, and it works out to about $1.75 per sheet! This is very attractive except for one thing. Will I be able to get negatives of the same quality as the lab's dip and dunk processor? I really don't want to start playing with the control strips, though. If I stick with the processing guidelines, and don't use control strips, will I be happy with the results? I need some encouragment here....
Last edited by Pasto; 06-03-2010 at 01:01 PM. Click to view previous post history.
You'll probably be perfectly satisfied with densitometry. However, you might want to practice your drying skills to avoid dust .
Thanks, I'm hoping you mean without densitometry....
Originally Posted by hrst
If you already have a Jobo I'd most definitely give it a shot.
I use my regular stainless steel inversion tanks and although I do my best to maintain temperature I'm sure it drifts a bit.
I have had results that exceed my expectations and I like to think I'm obsessed with image quality like most of us here or we would be shooting digital.
I don't own a densitometer, I don't run test strips and my C41 processed negatives print without issue using close to standard filtration in room temperate RA4 in trays. I use 2 different Kodak RA4 papers without major problems.
They even scan well.
Go for it.
I do my own C41 too
WIthout a densitometer or control strips, and the negs come out fine.
The big hassle with C41 is finding chemistry, without getting screwed on shipping cost. I bought a recent batch from Pakor, and the shipping/hazmat charges basically doubled the cost. >:-/
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I am one not afraid to take this on with less gear, and am happy with the results. I don't shoot a lot of C-41 4x5, but I am happy with my gear doing 4x5 e-6, and c-41 I run in smaller formats, no problem.
I started off without denistometry, but was gifted one,and now half assed run a control sequence. Prior to the denitometer I still ran control strips - home made, and they work with the machine reading now.
I make control strips with my wife in the front of the house out of direct sunlight, lit by the north sky (I'm in Canada), with a grey card held to one side of her face, and the color swatch patch page open from an old Kodak Color Darkroom data guide on the other side of her face. Frame in tight on just the cards and her smiling face, meter off the grey card, lock exposure, and with the motor drive, wind off a couple of 36 exposure rolls in quick succession.
I include about 4" snipped from one of these rolls with the first batch developed for each session. I printed them to find the enlarger/print chemistry filter settings for each session before I got a Lici Colorstar; now it automatically corrects for paper or print chem or film type drift as long as you feed it a grey card, and then analyse the first few prints of grey for a printing session.
I still use them to verify if I am getting good density, by reading the denisty of the grey card. I will recycle c-41 for up to 8 -80 sq inches of film if I can do them in short sequence from fresh, and usually there is 40 sw in in the first batch, and 40 sw in or less in the second batch. I scratch mix my c-41 developer, and find that I need 3:20- 3:25 for the second batch if done the same day, and 3:25-3:30 if there is an overnight gap between processing runs on the same chemistry. I try not to stretch it out. For non critical work I have found that two week old used blackish crud developer run though a coffee filter first will still do an ok, but not perfect job.
I have bleached 2.5" with c-22 bleach, and replenish 45ml per 80 sw in, until 1L of replenisher (same mix as working) has gone into a 1L of working solution. Currently I have a surplus of E-6 bleach, and so use it for 6' for c-41 film bleaching, as well as e-6 bleaching; iot is rated to 25 rolls per litre.
I process in tanks held in a temering bath that also warms my chemistry. It is a small cooler, filled with water and fitted with a fish tank glass tube immersion heater set to 100F.
You do not necessarily need a jobo
my real name, imagine that.
The short answer is no, you will not get dip and dunk lab quality easily from rotary processing c-41. That's not to say it's impossible, just really, really difficult (Besides spending gobs of time verifying proper dev. temps I ended up having to use a nitrogen gas feed to get consistently in-control processing). I spent weeks running, reading, and plotting kodak professional control strips with an x-rite 810 densitometer (I started a thread on this experiment from three years ago here on apug - it wasn't long before it was just a back and forth between me and PE which goes to show how very few people rotary processing c-41 have actually done this). And in all honesty they don't need to because the results they're getting are good enough...but still out of control. One year ago I'd suggest that if you were doing critical color balance work for a portfolio then getting an in-control process is of utmost importance and that without it you'll never have precise control over the palette. Now that there are no more optically optimized papers on the market I'd say it is no longer necessary since if you're serious about color balance you'll be scanning and making your adjustments in photoshop instead of working under an enlarger with papers designed for laser light jet.
I process my own C-41 5x4 sheets in a Jobo CPE-2 with lift.
Can a carefully controlled rotary process be as high quality as carefully controlled dip-and-dunk? I can't answer that question. I do know that when I first started using 5x4 C-41 I got my sheets processed by a local lab that caters exclusively to professionals - at appropriate high prices. I found their process to be dirty (specks, fibres) inconsistent and badly controlled (color differences across sheets, usually with a noticeble step in density in the middle of a sheet).
I have monitored my C-41 processing (home-made solutions) using process control strips and a densitometer and find that a) the process is bang on what it's supposed to be and b) I cannot detect differences between batches when using developer on a one-shot basis c) processing is within specified minilab tolerances when using the developer three times and extending the second and third passes to 3:30 from the 3:15 of the first pass. (4 sheets per pass, 350ml developer). This results in a processing cost of AU$0.40 per sheet if one-shot or AU$0.32 per sheet if using the developer to its capacity (3-shot).
Ok, I feel better about this Thanks to all for your comments and suggestions.
Peter, I'd be interested in learning more about your home-made solutions?? Also, when using the same developer 3 times, does this excede the capacity of the remaining chemistry (bleach, fixer, stab)?
Last edited by Pasto; 06-04-2010 at 12:53 PM. Click to view previous post history.
pm me. I have a whole binder of notes on c-41, e-6, (and c-22 and e-4 for that matter), that I would be pleased to dupe the relevant sections and postal mail them to you.
my real name, imagine that.