Getting density without a densitometer?

Discussion in 'Alternative Processes' started by eric, Aug 31, 2007.

  1. eric

    eric Member

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    I guess densitometers are out of my league in prices. Wow, didn't know they cost so much. Is there a different method? Can I use my spotmeter somehow?
     
  2. Lee L

    Lee L Member

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    Phil Davis published plans and methods for using 1 degree spotmeters as densitometers in his Beyond the Zone System books.

    Lee
     
  3. Dan Henderson

    Dan Henderson Member

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    Eric: check out Phil Davis' book, "Beyond the Zone System." He shows how to use a spotmeter as a densitometer.

    By the way, the EL Nikkor 105 is working great for me.
    Dan
     
  4. Nick Zentena

    Nick Zentena Member

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    My densitometer cost about $50 Canadian. It's almost older then I am but so is most of my darkroom stuff -)
     
  5. eric

    eric Member

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    Thanks guys! I just happened to borrow that book from the library a few weeks ago. Didn't like it much, it was a very old copy (70's I think). Just kinda flipped through it.
    I'll take it out again and look for the spotmeter. I didn't notice it then cause I guess I wasn't looking for it.
    FireP. -- glad the lens is working!
     
  6. Kino

    Kino Member

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    If you have a .10, .30 and .60 ND set of filters, you can combine them in various ways and directly compare the density over a light box.

    Just cut identical sized holes in a pair opaque cards and lay one over the NDs and one over the area you want to measure and compare.

    It should get you in the ballpark...
     
  7. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    You can also use your scanner if you have one. Many scanner driver software packages have a densitometer function built in.
     
  8. eric

    eric Member

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    hmmm, interesting. I'll look into that. I run GIMP on a Mac. I'll try googling some GIMP +densitometer
     
  9. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    Or look in the help files with GIMP (assuming it has any). I'm running SilverFast AI which came with my scanner, and I can use a densitometer in the scanner driver before I do my final scan, and of course, I can also do it in photoshop.
     
  10. Roger Hicks

    Roger Hicks Member

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    Dear Eric,

    Why do you need a densitometer? What are you planning to do with it? Consider that densitometers were all but unknown in amateur use until recently, and completely unknown in the early days of photography. Can't you use the time-honoured method of just making pictures, instead? Do not look for more precision than is needed, or meaningful...

    Not being combative, just wondering.

    Cheers,

    Roger
     
  11. dslater

    dslater Member

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    Hi Roger,
    Since this is the Alternative Process forum, I suspect the densitometer is a time saving device. AFIK, alternative processes need longer (sometimes much longer) exposures. This could make your film testing for speed and development times based on print appearance take quite a long time. It would be much faster if you had a densitometer to simply measure the density on the negative for film testing.

    Dan
     
  12. eric

    eric Member

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    Yep, exactly. I'm starting to do some Kallitype this weekend and I need a "base" starting point. Such as "my negs are x.x density, I have my UV bank of lights, it takes NN minutes for [whatever] exposure". This way, I can guestimate if my density increase x.x+, then perhaps, my exposure can be increased in the same logarithmic. But anyway, its just a base starting point, that's all. So I don't really want to buy one, I just want an effective way of getting some type of measurement in a measurable way.

    So far, I think the GIMP and/or Photoshop method might work (still haven't found the density settings in GIMP), or just basic spotmeter or the ND filter trick. All sounds good.
     
  13. dslater

    dslater Member

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    I wonder if you could use a 21-step wedge and just compare your negative to it in a light table?
     
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  15. sanking

    sanking Member

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    You could certainly do this. One of the Kodak densitometers was based on making exactly this kind of comparison.

    Sandy King
     
  16. eric

    eric Member

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    I will have to do some googling and read more about step wedges. I have no idea how to use them.
     
  17. Kino

    Kino Member

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  18. Roger Hicks

    Roger Hicks Member

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    Dear Eric,

    Fair enough. But Kallitypes (like all printing-out processes) are self-masking and were traditionally printed by inspection. As long as you have plenty of contrast, you should be OK.

    I've not made Kallitypes but I have made the closely related Argyrotype and although I have two densitometers (a working Heiland and a non-working comparison densitometer from the late 19th/early 20th century) I don't use a densitometer for this purpose. Exposures don't take that long and I find it quicker and easier to 'eyeball' what's happening than to make extensive measurements and calculations. After making a few, you can see what sort of neg will print well and what sort of exposure it will need.

    I fully accept that this is only one way of doing it, and that your route is another, but my feeling is that you'll learn to eyeball it eventually anyway, and that if you do it the traditional way (no densitometer) you may actually acquire that knowledge faster. Just a thought.

    Cheers,

    Roger
     
  19. Akki14

    Akki14 Member

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    Is there some chart I'm unaware of that tells you times based on density? If there was such a chart then I could see a densitometer being useful but for alt process stuff, experience and testing for yourself is the best teacher. If there was such a chart it'd have to incorporate how far from the bank of UV tubes and how powerful the wattage and how many tubes (possibly) etc. A split back frame for printing-out-processes would be infinitely more useful than an expensive gadget and experience will eventually come to you in the long run from actually doing the process rather than reading off pretty little numbers.

    From my experience with using a facial tanner unit with a bank of UV bulbs, exposures take a very long time for my cyanotypes - give me a bright sunny day over the UV box any day. It can mean the difference between 45minutes in front of the box and a maximum of 20minutes outside on a full sunshine day.
     
  20. Philippe-Georges

    Philippe-Georges Member

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    Roger,

    Your comments are sometimes a true relief, and this remark is NOT sarcastically intended!
    But I do confess, I have one to, but only use my X-rate 882 for E-6 and C-41, for B&W I use the little bit of guts I think I have.
    Alt processes are invented, and used at the time, by trial and error, I believe they should be practised as such, other wise the fun might 'evaporate'. But, of course, this is again a personal opinion (= attitude?)...

    Good Luck,

    Philippe
     
  21. Davec101

    Davec101 Member

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    I am just calibrating for Platinum and Palladium and am using a stouffer 21 step wedge (see attached pic) I dont have a reflective densometer, but do have a scanner. The image attached is what i have worked out to be my standard printing time ( the left hand gradiant is the one i have determined this on as it is a section of the transparency material i will be using)

    Anyway I was wondering if anyone could help me establish what my density range is and Dmax by just using a scanner and photoshop as i am unsure how to get such readings through a scanned image.

    many thanks
     

    Attached Files:

  22. sanking

    sanking Member

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    True kallitype, based on ferric oxalate, has very little self-masking.

    Vandyke Brown (VDB), which some people lump in as a kallitype process, is self-masking. VDB is based on ferric ammonium citrate, which gives rather different image qualities compared to kallitype.

    Practice today is to treat kallitype and VDB as separate processes.

    Sandy King
     
  23. Roger Hicks

    Roger Hicks Member

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    Dear Sandy,

    Sure, I accept their difference, but how can you have any printing-out process that is not inherently self-masking? You have far more experience than I so I would be interested to know how and why they differ in this respect.

    Cheers,

    Roger
     
  24. sanking

    sanking Member

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    True kallitype is not a printing out process. Where did you read that it was? It is primarily a DOP process and if any source states otherwise it is in error.

    Albumen, Argyrotype, salted paper and VDB are primarily POP processes.

    Some methods of palladium printing are POP, others are DOP.

    With most of these processes working conditions of high RH accentuate the POP characteristics,

    Sandy
     
  25. Roger Hicks

    Roger Hicks Member

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    Dear Sandy,

    That's the answer. Source forgotten, but obviously wrong. Thanks.

    Cheers,

    Roger
     
  26. dslater

    dslater Member

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    Hi Heather,
    I wasn't thinking of using the densitometer to determine exposure for your print. I was thinking of using the densitometer to measure the density of highlights on the negative so you can determine the development timed that yields a contrast range appropriate for your print process.