Around in circles with the Colorstar 3000

Discussion in 'Color: Film, Paper, and Chemistry' started by Tom Kershaw, Oct 30, 2009.

  1. Tom Kershaw

    Tom Kershaw Subscriber

    Jun 5, 2004
    South Norfolk
    Multi Format
    Firstly, thanks to Mick Fagan and others who have been helpful answering my questions on working with the ‘Colorstar’ type machines.
After a four hour attempt to calibrate my Colorstar 3000 analyser, I’m rather unsure as to how helpful the unit really is; after all, in four hours I could have made a good number of prints from my visually defined filter pack. Through the process of making 6 test strips on Kodak Supra Endura to test for a neutral grey from a grey (Expodisc*) 35mm Kodak Portra 400VC-2 negative. The 3rd strip seemed to give the most accurate result, the enlarger filter pack came to M:102, Y:114 - Meopta Magnifax 4a colour, (although the density was off by perhaps a 1/2 stop); only two units off on the magenta from the 104 magenta / 114 yellow pack I defined without the analysis function.

    Aside from the issues related to the 400VC negative reference negative; another issue that comes to mind relates to how the light is metered. My Colorstar only came with the diffuser attachment for the light probe, so I used the probe without the attachment for nulling the Colorstar LEDs; this method gave a exposure time of approx. 18 seconds @ f/8 which is correct for my process. However, when a pictorial negative is loaded in the enlarger, using the diffused attachment the density reading goes off, and the filtration pack seems rather arbitrary. The Frances Schultz articles seem to indicate using multiple probe attachments:

    If printing without the analysis function is assumed; work prints can made from standard filtration and fine control over colour balance and density can be made after viewing the work prints, which may be more nuanced than using the Colorstar anyway.

    In conclusion, I may well make another attempt to work to calibrate the Colorstar with newly exposed “reference” negatives, but I’m not sure how helpful the process will be...

    *The color visible through the viewfinder with the Expodisc 52mm attached changes depending on the lens subject; previously Mick Fagan has suggested an Expodisc reference grey negative is best made near to midday with a clear blue sky.
  2. tiberiustibz

    tiberiustibz Member

    Oct 22, 2007
    Tufts Univer
    A color analyzer is helpful in a very limited set of situations. I think the key is to choose one paper and one film (two films if you have to) and stick to it. I find that the most helpful way of determining proper color balance is to compare confirming strips to a neutral print you've already made. A color analyzer is helpful if you always shoot a grey card every time your lighting changes on every roll of film. Do you enjoy shooting grey cards? It also requires calibration, and as you say, they're only going to repeat your calibration, not help you refine it.
  3. Mike Wilde

    Mike Wilde Member

    Aug 10, 2006
    Multi Format
    I too struggled for a few nights to get the hang of my colorstar, but now it is like second nature.

    I have one set of three channels set for spot (the spot really just makes sure that you set the sensor base tilt head right to make the light fall onto the sensor at a right angle).
    The three settings I use are a neutral, a bit warm, and a bit cool

    The density setting and a tiny bit of colour shift is used to calibrate another three channels to read using the diffusing disc clip over.

    Mine is a 8 channel version; I keep notes in a notebook dedicated to the anlayser of what the channel settings are to get a good grass, or blue sky to analyse to no LED's in the star, and plug them into ch 7and 8 as the need may arise.

    I also use channel 8 to speed match the paper I am using when I print b&w and want to analyse it (which I do frequently

    The masters start set at 50, but I have old papers that have shifted, so I record the best masters to start with to allow it to autoconverge to a balanced test neutral grey to an autoprogram in one or two test prints. This is the power of this analyser to me. I can be away from ra-4 for some months,and be productive within half an hour of getting back to it.
  4. Ed Sukach

    Ed Sukach Member

    Nov 27, 2002
    Ipswich, Mas
    Medium Format
    It sounds to me as though a thorough re-reading of the ColorStar manual is in order. I've rarely had to make more than three test strips to intiially "calibrate" a new process - using "new" materials, chemistry, etc.

    I've found that the whole color printing process is FAR from stable. There are many variable that have a profound effect on the final aesthetic appearance of the image, e.g., age of chemistry, aging of the lamp in the color enlarger, lot-to-lot "shifts in paper color balance ... far too many to consider and investigate at every printing session. I keep track of the final enlarger dichro settings, but really only for use as interesting information relative to the process stablity ... never as infallible settings to be slavishly followed.

    It is not necessary to use some sort of "standardized" gray card image in the initial calibration, although the final image of a gray card can be comapered to the gray card itself, giving a usefully accurate evaluation of the entire process. A gray card image can be very useful when the 'balance" of the film deviates from the lighting of the subject - an example is te illumination of a model by the output of a transparency projector. I have a series of images made with a Hasselblad PCP80 projector and color slides of flowers. The lamp in that projector is operating at something like 3600K(?), and all bets are off anyway after the light passes through the transparency. Needless to say, the images, taken of "Daylight" balanced (~5500K) film, required LOTS of cyan filtration.

    A gray card is useflu, but not absolutely necessary; a channel can be "set" for "Fair Caucasian Skin" (or "Black" -- or "Heavily tanned"...) and be of great use in portraiture.

    I have three (3) ColorStar 3000s - (long story...) and vivid memories of the struggles to print color without them.