|
|
|
-
My bulb is only a foot-and-a-half above the paper - far too close for a spotlight to give even coverage. That's why I have to use a flood light.
When I started with Azo, I was exposing and developing by the Fred Picker "thinest negative" principal. Then my exposures were running 10-30 seconds. Now that I've adopted the dense negative system (discussed here and at michaelandpaula.com at length) my exposures have been from about 50 seconds to 3-minutes. I consider myself still at the experimental stage with this system. These negatives are so dense they'd break Don Miller's densitometer (ha) but they print well if I expose long enough.
juan
-
After experimenting with a few things, lately I've been using a cheap halogen desklamp with the UV filter removed and a little over a foot from the paper (8x10"). Exposure times are around 20 sec., but I've burned in a few very dense highlights for as long as 3-1/2 min.
-
There is another reason to use a bright bulb besides keeping the exposure times short, and that is so that you can see through the negatives, especially the dense ones, so you know exactly where to dodge and burn.
-
Just finished my first trial with Azo and I realise how important a properly exposed dense negative is. I started out with a 200w bulb but moved on to a 60w bulb in order to keep the exposure times not too short (i.e. less than 15 secs). My thin negatives did not show as much detail as my denser negatives. But what a glow those dense negatives printed out. Beautiful prints and tone and detail and etc.. By the way, I used the two bath Moersch Amidol plus kit (the second bath being Catechol). Works very well indeed.
-
 Originally Posted by Francesco
Just finished my first trial with Azo and I realise how important a properly exposed dense negative is.
What criteria are you using to determine that they're properly exposed (i.e. dense enough)?
-
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
-
I make four negatives of the same scene exposed differently and developed differently. One of the negatives being exposed and developed as I always do and the others follow a procedure described by Michael Smith in the forum. I visually compare all 4 negatives on the lightbox before contact printing them on AZO. In all cases, the most dense of the four (that is, the one that appears the darkest on the lightbox, and yet also appears to have the greatest amount of highlight and shadow detail) is the one which prints out the best (and easiest?) on AZO. This negative turns out to be the one which I gave 1 to 2 stops more than my metering would suggest and 20 per cent more development time. It took a lot of faith for me to try this procedure as I was afraid to overexpose the negative. No such luck. Plus, the film I use is Efke PL100 which I believe handles such extra exposure and development well.
-
Jdef, I too do not understand the densitometric qualities of this procedure but it does show some interesting results and matches the longer scale of AZO well. Have you checked this thread from the AZO Forum - www.michaelandpaula.com/mp/startframe.html? The discussion here is about density and is quite in depth. I use Pyrocat HD 2:2:100 and this I think is an important factor to consider. Other used ABC Pyro. You are right when you say that shadows are moved up (e.g. Zone IV instead of II). And you are also right when you say highlight are moved up too (e.g. Zone XII instead of VIII). What is clear is the difference between these negatives and those I expose as I normally do. The latter do not print so well in AZO, which is really the reason for making such negatives. Let me know what you think of that thread in the AZO forum because maybe you can explain it better to me.
-
I think the thread Fansesco is talking about is the 'ABC, pyrocatHD, film choice' one located in the 'Developing Film' section.....but I could be wrong.
-
SPixel is right. Go to the Developing Film section and look for the thread ABC, Pyrocat HD, Film Choice".
-
I have followed this thread with a great deal of interest. There seems to be an awfully lot of "black magic" and very little of sensitometry as I observe some of the people who expose film for and then print it on Azo paper.
In the midst of all of this confusing information I decided to conduct tests of the materials to see what the materials themselves indicated. I began these tests with the paper using a reflection densitometer exposed to a known density in the form of a Stouffer calibrated step tablet. My reason for doing this was that the Azo paper is a fixed grade material and for that reason it's sensitometric performance is fixed.
What I found was that Azo grade two has an exposure scale that will accomodate a negative of 1.60 density range (high value density minus low value density and not minus film base plus fog). I found that grade three Azo will accomodate a camera negative having a density range of 1.10.
The matter then becomes one of selecting a film and developer that will produce a density range that matches the paper. Not all films are equal in this respect. Furthermore not all of the same speed from differing manufacturers are equal in this respect. There is one way to know the film's characteristics and that is to test the film. Everything else is hearsay, rumor, and rethoric.
When some people indicate that they are rating a 200 speed film at an EI of 100 and placing their shadows at Zone IV and then further state that this indicates a two stop decrease in speed from the mfg rating I find that I must question their reasoning. This doesn't represent a two stop decrease but rather a four stop decrease from the manufacturers rated speed. If the film exposure breaks at Zone three then the film is incorrectly rated.
When we move the lowest values four stops up the characteristic curve of a film what happens is that we move the entire exposure up the curve. This would not be a problem except that film curves for the most part have limited straight line portions to the curve. In the case of a four stop overexposure we would place our highlights on the shoulder of the curve. This leads to poor highlight separation at the expense of better shadow separation. This is further complicated by the fact that the compressed highlights located on the negative's shoulder are then placed on the toe of the papers characteristic curve. This serves to increase the compression of highlight tonal scale still further.
Additionally for those who use staining developers the beneficial stain aspect of a camera negatives density is proportional. What we find in this consideration when film is overexposed is that the stain density is further compressed from what would be the case in a properly exposed negative because we have a higher value in our low density to show the stain density effect.
I have no argument with those who wish to expose film in whatever way that they choose. I just don't buy the fact that the rules of the sensitometric characteristics of film, film developers, and paper have somehow been magically repealed.
|
|
Adv Reply
