Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 68,767   Posts: 1,484,173   Online: 863
      
Page 3 of 3 FirstFirst 123
Results 21 to 30 of 30
  1. #21
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,723
    Images
    65
    Kodak prints a book on color printing with examples and CC filters.

    From an experience standpoint, you have to remember that I helped design one of the versions of Kodak color paper (Ektacolor 30/37) and have coated it and processed color papers for nearly 50 years. I will try to help as much as possible, and often due to the interposition of digital scans it makes my work harder, but I will do the best I can to pass on my skills.

    I am thinking of a workshop in advanced color printing to cover a host of things I see here on APUG and on PN as well. I want to help, but please don't consider me omniscient or omnipotent. I'm just experienced.

    PE

  2. #22
    MattKing's Avatar
    Join Date
    Apr 2005
    Location
    Delta, British Columbia, Canada
    Shooter
    Multi Format
    Posts
    11,591
    Images
    59
    The second example looks to me as if it might be of a scene lit with one or more stage lights. As such, there could be gels used in the light source, and the source of illumination could be any of a number of sources, with any of a number potential colour temperatures.

    This is a very hard way to learn colour printing! :o

    It is sort of like trying to learn to print black and white, using the most difficult negative available.

    I would suggest that for your first colour printing experiments, you try to use a negative that you have reason to believe yields a well exposed, colour balanced print. If you have an example print, that appears well done, from the same negative, then there is no shame in trying to duplicate it, and much to learn from the exercise.

    If you don't have such an example at hand, try to use one that records a scene with even light, of reasonable contrast, and consistent colour.

    Once you have acquired facility with the straightforward negatives, there is a world of difficult negatives out there to take on (if you need any, I'm sure I can find some amongst mine )

    Good luck, and enjoy yourself!

  3. #23

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    Quote Originally Posted by digiconvert
    Now ..further questions;
    -I assume that like mono work I discard the dev and keep the Blix, is that correct ? How long should the Blix last once diluted ?
    -I have looked at the options for processing other than in trays. The most cost effective seems to be a Jobo Roller base and a paper tank. Can this be used with Jobo bottles as with a CPE i.e pour the chem in by screwing a bottle on and inverting ? Anyone any advice on timings/technique with this ?
    -Anyone any suggestions as to a cost effective way of processing C-41 for a film a month ? I have heard a bowl of warm water is adequate-comments ?

    I've described my setup way too many times-) Do a search. Basically I use Jobo tanks for both film and paper. For tempering I use a picnic cooler with a fish tank heater. To roll the tank I use print motorbase hooked up to a gralab 300 timer. Works just a perfect for paper and film.

    If you really mean 1 roll at a time then the system isn't for you. It only works with the midsized tank [5 35mm or 3 120 at least] You could put one roll in the tank but you'll waste chemicals. OTOH for 120 even putting one roll in the tank wastes less chemicals then a normal inversion tank would.

    On the question about blix and chemicals. The chemical docs should tell you that. I reuse everything for RA-4. I make up 2x the blix that I do developer. Blix has never gone off for me. OTOH developer won't keep that long. If you're doing a prewash it'll keep better. If not the paper will suck up developer. Leading to half full developer bottle.

  4. #24

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    Quote Originally Posted by ggriffi
    In the color class that I took we had a set of "color correction" filters that we used after getting exposure correct to help with said correction, I believe that I have seen these listed in a freestyle catalog.

    Freestyle


    g
    Viewing filters? I never got the hang of them.

  5. #25
    Ed Sukach's Avatar
    Join Date
    Nov 2002
    Location
    Ipswich, Massachusetts, USA
    Shooter
    Medium Format
    Posts
    4,520
    Images
    26
    Quote Originally Posted by Photo Engineer
    The second was that a 0.05 density change is supposed to effect a 0.05 log E change in speed of a layer. I have heard all of the arguments you state, but having done actual sensitometry across dozens of color enlargers and cc filters, I have found that to be true if the filters have not faded appreciably.
    PE
    I agree, a change of .05 "density change" is supposed to effect a change of .05 gamma...
    But that was not what I was saying. The calibration of dichroic color heads ("cc" units) does *NOT* seem to conform to any given standard. As far as I can tell, there is no guarantee that a 5 "cc" change will result in a change of .05 in filter density. Kodak. Leitz, and others do not seem to follow the same linearity - that is why Ilford gives different contrast modification numbers for different enlarging systems.
    Carpe erratum!!

    Ed Sukach, FFP.

  6. #26
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,723
    Images
    65
    Ed;

    Three things you should be made aware of.

    First, a change in cc filter does NOT change gamma, it changes relative speed. These two characteristics (gamma and speed) are two different things. One is the slope of the curve and the other is the sensitivity of the layer to light. Only the latter is related to cc filter changes.

    Second, in my experience with both Chromega and Beseler heads (I have both and have used many more than those at EK) and my cc filters, I find that depending on filter density a 0.1 change or a 0.5 change takes place with a corresponding fresh filter of whatever sort (CC, CP, Dichro, etc) and gives just about the same result.

    When measured, the density and speed change is roughtly equal to the on peak density of the filter as well, regardless of filter. I have measured these on-easel with a spot photometer.

    Third, the reason that Ilford gives such data is because the sensitivity of MG B&W paper is quite different than color paper in the green region and therefore responds differently to the magenta filtration factors and blue filtration factors, but color paper has a different response. The CC filters were designed for color paper peak sensitivity.

    I have recently posted a wedge spectrogram of Ilford MGIV paper in another thread. If you move the green peak several units to the right on that plot, you will begin to approximate the green sensitivity of modern color papers.

    PE

  7. #27
    digiconvert's Avatar
    Join Date
    Nov 2005
    Location
    Cannock UK
    Shooter
    Multi Format
    Posts
    809
    Images
    51
    Quote Originally Posted by Nick Zentena
    I've described my setup way too many times-) Do a search. Basically I use Jobo tanks for both film and paper. For tempering I use a picnic cooler with a fish tank heater. To roll the tank I use print motorbase hooked up to a gralab 300 timer. Works just a perfect for paper and film.

    .
    Yes I found your set up when I was considering a TBE - seems a waste of time(TBE not your set up )- and it's one of the things that made me think home processing was a possibility without spending a fortune. So Thank You

    As for the other advice thanks a lot - I think I'm going to have some fun !

  8. #28
    digiconvert's Avatar
    Join Date
    Nov 2005
    Location
    Cannock UK
    Shooter
    Multi Format
    Posts
    809
    Images
    51
    Quote Originally Posted by Ed Sukach
    I agree, a change of .05 "density change" is supposed to effect a change of .05 gamma...
    But that was not what I was saying. The calibration of dichroic color heads ("cc" units) does *NOT* seem to conform to any given standard. As far as I can tell, there is no guarantee that a 5 "cc" change will result in a change of .05 in filter density. Kodak. Leitz, and others do not seem to follow the same linearity - that is why Ilford gives different contrast modification numbers for different enlarging systems.
    I can't pretend to understand much of this. I'm a trained lab technician so I always work on the 'suck it and see' methoid - if it works the theory can go hang

  9. #29

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    If you go the picnic cooler route don't skimp on the cooler. Bigger is better. The downside is it'll take longer to heat up but once it's up to temp it'll hold temp for a long time. Also make sure it's got a drain.

  10. #30
    Ed Sukach's Avatar
    Join Date
    Nov 2002
    Location
    Ipswich, Massachusetts, USA
    Shooter
    Medium Format
    Posts
    4,520
    Images
    26
    Quote Originally Posted by Photo Engineer
    Three things you should be made aware of.
    First, a change in cc filter does NOT change gamma...
    I feared as much... I did not make myself claer.

    The point I am trying to make is that *All enlargers" - more properly, All enlarging fitration systems are not created alike. What serves as 5 cc change in one is not necessarily the same in another.

    The example I was thinking about is dervied from the Ilford Filtration Tables, that allow a dichroic head to be used in controlling the contrast of Ilford Mutigrade Paper, from Table 5, in the enclosed data sheet:

    To obtain Grade "0" contrast with a Durst (max 170M) head, use 100Y/ 5M as a starting point. For the same contrast, with a Durst (max. 130M) head, use 88Y/ 6M; Kodak, 90Y/ 0M; and Leitz Focomat V35, 105Y/ 12M.
    These settings should (~) give light with the same color balance to effect a contrast grade of "0".

    In the middle, Grade 2 1/2, Ilford recommends Durst (max 170M), 42Y/ 28M; Durst (max 130M), 35Y/ 31M: Kodak, 32Y/ 42M; and Lietz Focomat V35, 32Y/51M. At Grade 4 1/2, Durst (170M max.), 10Y/ 105M; Durst (130M max.), 6Y/ 89M; Kodak, 0Y/ 150M, and Leitz Focomat V35, 15Y/ 154M.

    All these different head settings are calculated to give the *same* mixture of magenta and yellow in the light from the enlarger. The paper itself has little, if anything, to do with it... Which is my point: "All enlarging heads are not equal in "cc" unit correction. My experience, admittedly limited, supports that information. A change of 30 "cc" does not necessarily (in fact, rarely will) result in the equivalent of .30 (one stop) change in the dichroic filters. It will, accurately, in the density control filter of my Omega D5500.
    Carpe erratum!!

    Ed Sukach, FFP.

Page 3 of 3 FirstFirst 123


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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