Or directly from Stouffer Industries, http://www.stouffer.net/
Originally Posted by JMoore
Wide range of sizes of both reflective and transmission step wedges.
I have a densitometor at my lab , it is invaluable for keeping chemistry lines in proper plot,
Though I have to admit that I do not use it as I have a technician working with me that is a braniac when it comes to sensitometry.
My strong skill is evaluating negatives visually and making adjustments accordingly when processing film.
Kodak use to have a book on evaluating a negative over a sheet of finley printed page, looking at the type through the shadow area and the highlight. You should barely be able to read the type in the highlights. The longer you look at negatives and make prints the better your skills in evaluating will become.
To run some of our computer equipment a densitomater is mandatory as it reads the 21 step wedge and corrects the lazers to fire off the correct exposures for printing on various medias.
As Sandy points out it is a bit of a necessity if you want to further explore the ** possibilitys ** of film and paper and how one can affect them with exposure and development techniques.
As others point out it is not necessary to make good film and prints. For sure August Sanders and Josef Sudek did not have a densitometer and I think they did pretty well without.
I think the decision would be right when you feel you absolutely need one to improve your work, and not before.
[QUOTE SNIP >>>>> SNIP.....There is no right or wrong answer to the question of whether one should or should not get a densitometer.......
However, much of what the densitometer does for you, especially at the printing stage, can be done with a 21 or 31 step transmission wedge so I would strongly urge you to get one of these guides and learn to use it. You don't need a calibrated one since the small differences between the uncalibrated ones are inconsequential at the printing stage.
Without messing-up this thread can / would someone explain how one uses a ' 21 step ' transmission wedge. Am I correct , it is placed in neg. carrier or over a sheet of paper as a test for 'Contrast / Exposure'
Barrie B. or am I way off the mark???
Why the big deal? You may have already seen my
post this thread. I like the Tobias TB+. I got it from
eBay for under $80. Shop around? Dan
If you include shipping I think my 4x5 transmission from Stouffers cost me more then my colour densitometer did. I wouldn't suggest anybody rush out to buy one but the things are almost being given away. Even my colour analyzer has one built in and those things aren't selling for big bucks either.
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The trouble is, the most useful use of a densitometer is for analyzing the results of usine a step density wedge. If you have that, you can get along without the densitometer for finding contrast index, etc.
yeah - just making sure we are not putting the cart before the horse.
Originally Posted by sanking
I'll look into the second part of your post later.
Last edited by Kirk Keyes; 01-23-2005 at 12:25 PM. Click to view previous post history.
Originally Posted by rootberry
In addition to purchasing the Stouffer Step Wedge which others have suggested and which, I agree, is very useful, try to look at your process as a whole system with individual parts that can be tweaked to your satisfaction.
1. Film speed test to determine your personal ISO. I find that a .10 Neutral Density Wratten filter is helpful here. I use my spot meter on a lightbox to measure the density of clear film base+the ND filter. This is film-base plus fog (FBF). I then run a film speed test for a Zone I (4 stops down from meter of a Kodak gray card) and try to match the density of the exposure to that of the FBF.
2. When I've got that, I expose several sheets for Zone VIII (3 stops over the meter of a gray card) of an even-toned subject (out-of-focus untextured surface) and do a development time test. Using a print time arrived at by test strips to produce the shortest exposure time for maximum black through a clear piece of film (FBF), I test the first sheet. If the development time is right, there should just be a hint of density that is distinguishable from the pure white of the unexposed paper border. If you can't distinguish border from the exposed part, increase your development time 20% or so and try again. If there's more than a very slight difference, decrease your time accordingly. You should get it on about the third or fourth try. Once you've got it, this will be your basic exposure/development combo for that film and paper combo. Your contact prints should then give you a maximum black (if your subject had one) and your brightest highlights should still be discernible.
I've managed to survive 35 years without a densitometer, and except on very rare occasions, have never felt the lack of one.
Efke 100 is far superior to J&C 200 if azo is the choice. It has the ability to build density and contrast, both of which are helpful when using this paper. It also is one of the best films available with respect to expansion or contraction of contrast.
Efke 25 is also a good film, but is a bit more touchy with respect to exposure and development. This is a great film for showing off metals or hard paint, but lacks some of the easy expansion and contraction potentials inherent in Efke 100. Short development times or increased dilutions are the key to using it.
Well, I disagree a bit on this. I find the densitiometer very useful in making initial decisions with a new negative about printing speed and the type of contrast control that will be required. I measure the shadow values, which tell me how long exposure should be, and then the highlights. Substracting the shadow from the highlights gives the negative DR which I can then used to determine how to control contrast.
Originally Posted by gainer
If you are working with an alternative process such as platinum this way of working can save a person a lot of time and expense over trial and error. I know that some people claim that they can just hold a negative up to the light and immediately know how long to print and what the contrast will be, but unfortunately I am not that talented.