Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,928   Posts: 1,522,164   Online: 1022
      
Page 1 of 4 1234 LastLast
Results 1 to 10 of 39
  1. #1
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,095
    Images
    12

    debug my RA4 process? (insane contrast)

    I've just started RA4 but am having trouble with the contrast being stupidly high. Witness a dodgy iPhone photo of the print:

    compared to a scan of the negative (compare forehead vs green cushion!)...

    That's from Portra 160 I developed at home in brand new Fuji chemistry.

    Process details are:
    - Ektacolor RT/LU, mixed up 1L of developer-replenisher (40+17.8+40mL into 1L as per J39)
    - separate bleach and fix, mixed at 1+4 and 1+6 respectively (same concentration as they would each be individually in the blix)
    - 200mL working solution, to which I added 5mL starter (j39 says 25mL for 1L of solution)
    - remaining 800mL used as replenisher at 10mL/sheet
    - Fuji Crystal Archive
    - process in Jobo at 35C as per Table 5 of J39 but separated blix:
    - 1:00 prewash, 2 baths (some blue dye comes out)
    - 0:45-0:50 develop
    - 0:30 stop bath (2% acetic)
    - 0:30 wash
    - 0:45 bleach
    - 0:30 wash (3 dumps of water)
    - 0:45 fix
    - 2:00 wash

    I don't have any control strips

    The filter pack is 15M 10Y, which seems a little on the cyan side. Might be that my enlarger bulb is dim (it's a 200W in an enlarger with cooling intended for a 250W so might be running cool).

    Reading Ctein's Post Exposure indicates that crazy contrast might be due to insufficient "Part A" in the developer. I measured it to within less than 1mL (2%) though and it was the same quantity as Part C. And the tide in my Part A and Part C bottles is the same.

    The stupid contrast looks sort of like bleach-bypass processing to me however "dead blix" is generally listed as giving a yellowed Dmin and my whites borders are quite clear. I'm going to mix up some combined blix as per instructions now to test whether the separated operation is breaking anything. I've also got some lab-developed negs here to test with in case my C41 process is whacked but I control that pretty tightly and my home-souped negs don't look contrastier than the shop-souped ones.

    Desperately seeking ideas...
    Last edited by polyglot; 06-15-2012 at 07:42 PM. Click to view previous post history.

  2. #2
    markbarendt's Avatar
    Join Date
    May 2008
    Location
    Ignacio, CO, USA
    Shooter
    Multi Format
    Posts
    5,589
    Blog Entries
    3
    Images
    19
    Color balance seems to be one issue, that may be part of the issue.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  3. #3
    E76
    E76 is offline
    E76's Avatar
    Join Date
    Mar 2008
    Location
    Rochester, NY
    Shooter
    Instant Films
    Posts
    375
    Images
    13
    It could be a measurement issue. When you mix such small quantities your precision needs to be extremely high. This is why Kodak does not recommend mixing any less than the full 10L at a time, which I would do anyway. If stored properly, the RA-RT chemistry lasts a very long time with replenishment (almost a year in my case).

    I'm a little confused by your fixer step at the end since you are using Kodak chemistry. Why did you decide to separate it? It's possible that your bleach is not working correctly and you have some retained silver in the print, which will decrease saturation and increase contrast.

  4. #4
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,927
    Images
    65
    As you say, the contrast is too high, but the balance is also too blue.

    Some report that Fuji CA has higher contrast than Endura, but it is also true that many papers just cannot get the full tone scale seen in a negative scan.

    PE

  5. #5
    markbarendt's Avatar
    Join Date
    May 2008
    Location
    Ignacio, CO, USA
    Shooter
    Multi Format
    Posts
    5,589
    Blog Entries
    3
    Images
    19
    Good catch E76.

    If I remember correctly RA "Blix" is more efficient at it's job than separated RA "bleach and fix" steps.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  6. #6
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,095
    Images
    12
    I'm pretty confident of the measuring, since the syringe approach has worked very well for me with both C41 and E6 - I have perfect chromes after making up 1L batches from a 5L kit. Same sort of ratios as here. Perhaps J39 is not applicable to RT/LU and the ratios are a bit different - the concentrate bottles don't state their contents volume so I can't divide the volume by 5 myself without pouring it all out to measure and therefore losing some to left-behind drops etc.

    I just did a test with blix instead of separated bleach+fix and the contrast* is unchanged, so I don't think the problem is that separation. The reason I separate them is because of the shelf-life once mixed: I can store a litre or two of bleach or fixer on the shelf for months to a year but as blix, the bleach will eat the fixer in a couple of months. According to PE, separating them is fine and my test seems to confirm that the separation didn't change anything.

    In terms of mixing the developer, I could make up a full 5L (it's the 4x5L kit) and store it in a wine-bag. That's about 300-500 sheets worth though so I'd want to be sure it was going to last a year or two without refrigeration! I can store a 1L bottle in the fridge without getting into too much trouble but a cask would have to sit in the cupboard. Actually I think I'll just do this anyway - I have 4 of the 5L sets, which even if this one dies in a year, will still be lots of printing. And it will allow me to determine if J39 is applicable.

    Edit: it may or may not be too blue. The white cloth in the right of the frame appears as a neutral grey. I think the crazy look of the skin is just due to the contrast and/or my bad phone-picture.


    * actually the print is badly cyan-fogged but I assume that's due to my darkroom not being properly light-tight in the daytime, whereas the print I posted above was done at night and has no fogging. Other than the cyan, the print densities look the same with blix vs separated bleach+fix. Unless somehow going to the blix could cause a massive and uneven shift to cyan...

  7. #7
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,927
    Images
    65
    Blix vs bleach then fix is not problem here. Don't worry. The bleach then fix was and is used commonly by some processors for color paper and should be used for all film processors.

    All Kodak chemistry I have has volumes printed on each part so as to make up a good small batch. So, this may be the problem as the ratios are different from those I used for the replenisher, but then things change over time. I suggest you check the pH. It should be 10.5 when ready to use. If it is not, then there is a mixing problem. As pH goes up, contrast goes up.

    PE

  8. #8
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,095
    Images
    12
    I got a good print out of it but changed about 3 things. Narrowing it down now.

  9. #9
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,095
    Images
    12
    Well, I don't know. I now suspect that my C41 process is overdeveloping.

    I've made a good print from some test shots that I had developed at a lab. I've also made good prints from an identically-exposed roll that I developed at home, except that the print exposure required differed and there is slightly more contrast in the print from the home-developed negative.
    - Lab neg prints at M15 Y7.5 and 2.7 stops (6.5s); about 2CC blue and a tad underexposed
    - Home neg prints at M7.5 Y5 and 3.5 stops (11.3s); looks damn good, though much contrastier than I expected from Portra160!
    The negs look practically-identical to the eye though.

    The print from lab-souped film (you can tell I shot this to have a good selection of colours and tones):

    And from home-developed using Fuji Hunt 5L kit:

    Sorry I don't have a flatbed scanner, just film scanners

    The iPhone-photos over-state the difference in brightness between the two. The former does have better brightness in the wooden table but it has less overall exposure and the latter shows much better highlight detail, especially in the HP5 & Acros boxes. While these differ slightly, the still-significant contrast of the lab film indicate to me that perhaps this paper is just really high-contrast. And maybe I over-developed the baby-photos roll; still got a few more combinations to try yet...

    I vaguely recall that it's possible to reduce contrast chemically, e.g. by adding sulfite or something to the developer. Which sulfite? How much? Say I wanted a 1-stop contraction, what would I do?

  10. #10
    Athiril's Avatar
    Join Date
    Feb 2009
    Location
    Melbourne, Vic, Australia
    Shooter
    Medium Format
    Posts
    2,494
    Images
    28
    Did you add the 24mL of RA developer repenisher additive?

    Did you develop in straight replenisher? Or did you dilute it to working solution and add starter?

    http://www.kodak.com/global/en/profe...is49/cis49.pdf


    edit: Just looked at the data more closely, 40/17.8/40 matches up to RT working strength (instead of replenisher) without the additive. But it's still sans starter. I'm under the impression it's RA you don't need the starter for, not RT.
    Last edited by Athiril; 06-16-2012 at 02:45 AM. Click to view previous post history.

Page 1 of 4 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin