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?
hmmm, interesting. I'll look into that. I run GIMP on a Mac. I'll try googling some GIMP +densitometerYou can also use your scanner if you have one. Many scanner driver software packages have a densitometer function built in.
Dear Eric,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?
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
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
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.
I wonder if you could use a 21-step wedge and just compare your negative to it in a light table?
You could certainly do this. One of the Kodak densitometers was based on making exactly this kind of comparison.
Sandy King
Dear Eric,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.
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
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.
Roger
Dear Sandy,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
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
Dear Sandy,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.
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.
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