I was sort of surprised myself. I think the reason that I started shooting so much over exposed was that I was so erratic and uneven when I first started shooting that I needed a lot of cushion, a lot of room for error so that i wouldnt grossly under expose, but now im less inclined to underexpose and so my exposures have all been several stops over consistently.Another thing... You've proved that the manufacturers do actually know what they are doing! Their recommendations, film speed and development times, generally work out OK... So, if we rely on their suggested settings we can concentrate on the art of photography while applying the craft as we understand it should be... Fred
Agreed, temperature does make a difference... to contrast but not density. But I beg to differ about your view regarding the relationship between exposure & density. It is very easy to confuse the terminology used concerning the cause & effect of density and that of contrast. If you have a look at images in post #21 - a contact print, you will notice the detail becomes less obvious the more the film frame is over exposed. i.e. The film rated @ ISO 400 yields detail of the target whereas the same film frame over exposed by 2 stops - ISO 100, does not. Thus, it can be seen that exposure changes density all else being the same. Also, it will need a longer print exposure time for the ISO 100 rated negative to achieve the same reflectance outcome compared to the time used for the contact printed ISO 400 negative. Careful control over the development process allows one to control the overall contrast range of the negative so as not to lose detail in the highlights - the exposure being made for the shadow detail. FredI don't really think exposure do add density to negatives. Its the development time and agitation that adds the density. Temperature do play a role too.
Ahh...very good! Thanks so much for explaining that.Hello again... I would interpret your data as follows: a 0.3 density approximates 1 stop thus if you divide the low reading into the high reading of each test then then you arrive at the brightness range of the negative in "stops" of exposure. So, at box speed, normal development, the range is around 6 (5.76) stops which is perfect for printing on a mid grade paper. The next test, 1 stop over & under developed 15% yields in this instance a 7.65 stop range - a negative with clearly a longer tonal range with more shadow and highlight detail. And, the 3rd the result a much longer mid tonal range. Probably tests 2&3 will need to be printed on harder paper grades. This is my take on the information. Maybe one of our still asleep experts will chip in tomorrow.
Lastly, if you can for each of the tests measure the density of only the grey part of your "grey card" for both the 400 and 100 ISO exposures then with this information it will be possible to calculate a "ball park" contrast index - a measure of your development process. Fred
of course exposure adds density;so does extending dev time and raising temp.expose for the shadows and dev for the highlights;I don't really think exposure do add density to negatives. Its the development time and agitation that adds the density. Temperature do play a role too.
the negative density target value for Zone V is 0.72Ok...here goes.
Grey card numbers for each ISO at each dev time.
Box speed at stock dev time
1.3
ISO 200 at stock dev time
1.46
ISO 100 at stock dev time
1.7
---------------------
Box speed at -15% less dev time
1.31
ISO 200 at -15% less dev time
1.49
ISO 100 at 15% less dev time
1.7
-----------------------
Box speed at 30% less dev time
.89
ISO 200 at 30% less dev time
1.08
ISO 100 at 30% less dev time
1.28
There they are in all their glory. As I said, they don't mean much to me at this point, I welcome your observations.
It read 1.07 for the brightest highlight / .12 for the deepest shadow
Thankyou.the negative density target value for Zone V is 0.72
Well, that gives me something to aim for.1.07-.12 equals an overall contrast of about 0,95.
If this printed nicely on your grade 2 paper, then things are "just all right", beause grade 2 paper is intended to print a negative with a contrast of 1 nicely.
Wow, them's some bulletproof negs!
Gray card readings want to be between .65 and .75, depending on whether you use condenser or diffusion enlarger. Highlight densities typically shouldn't exceed 1.15 to 1.20 for 35mm negs
As Ralph noted, I think you have some exposure issues (meter or shutter problems). Could also be densitometer is not reading properly. Have any 21 step Stouffers transparency strips? I think you definitely need one for reference.
Or you're agitating "cocktail shaker" style, but I don't even think that would give you numbers like you're seeing..
Get Ralph's book "Way Beyond Monochrome" or Horenstein's "Beyond Basic Photography;" both are excellent.
Ahh! Good question, ill get to checking, it shouldnt be too longSomething's definitely not kosher!
If using a proper gray card set up in good light and you are using the reflected meter reading that does not include any specular reflections (reading taken at a 45 or so), with manufacturer's recommended development and ISO rating, you should be seeing around .30 film base + fog, .70 - .75 for middle gray. FB+F should be measured between frames or on the unexposed leader.
Visually, how to the gray card renditions on your negs compare with the Stouffer step wedge? You should be able to make a pretty good eyeball comparison on a light table.
Ok Here is the first strip put on my iPad as a light box next to the step wedge. I took the picture with my iPhone and brightened it up in lightroom because it was a bit dark.If I remeber correctly, step 6 is .75 and each step is .15 on the 21 step wedge. Check to see how close your gray card renditions on the negs are to step 6. Step 9 is 1.20 and this is what you are shooting for as a max highlight reading. See if you can read newsprint through step 9.
When in school, if I turned in an assignment negative with a highlight density reading greater than 1.20 (not including speculars), it was an automatic 'F' for the assignment!
Ok.Xlnt, we can now see what you have. I'm thinking the negs are overexposed. Can you provide exact details for exposure and development?
Ahh..I should have said it was XTOL 1:1, sorry.Okay, been puzzling the data provided. I'm going to assume that the Microphen was diluted 1 to 1; that's the dilution for 12 minutes. That said, having to reduce development by 30% to get the gray card on zone V tells me you are overexposed by about two stops. The gray card test exposure should be 16/500 when photographed in clear sky sunlight. Have you checked your meter in the camera? Is the exposure compensation dial moved off zero?
If you didn't dilute the Microphen 1:1 and developed 12 minutes you would get results close to what you are seeing.
Edit: I did notice in your last post that when I zoomed on the iPad the rebate info is darker on the gray card strip vs. the non-test strip. The top strip rebate info looks like my Ilford film; the test strip appears to be developed more.
OK...thanks. That's what appears to be happening.Anytime you have to reduce development by 30% to get middle gray on Zone V, that tells me that the film was overexposed by two stops. That's the only conclusion I can reach with the current indications.
Ok. I happen to have a fresh bag of D76, I'll mix up and use that.I would suggest at this point that you repeat the test with D76. Film manufacturers base their specs on how the film behaves with this standard developer. All other developers will introduce some variables which can throw off results.
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