i prefer landscape photographing. for film testing as lambrecht descripes i need daylight or a daylight bulb.
i want to use a daylight bulb because actually light conditions changes too fast.
can you also recommend a daylight bulb for fim testing in this situation?
whats with the setup?
just photographing a white-sheet of paper in my room?
Although any light source other than real sunlight is a compromise, the repeatability of artificial light sources makes them a good compromise, if your tests don't need to result in laboratory grade accuracy. For example, my purposes I would be happy to be within 1/3 stop accuracy, 2/3 stop is tolerable. Once I get into the field to take pictures, I can't get my light meter readings to within 1/3 stop accuracy/repeatability anyway.
i work with a hasselblad 501cm.
i put the stouffer 6x6 just into the film holder and make a contact print.
it seams to work (did a test on one foto, the bars are fine)
shooting 5 films with one holder costs time so i'm afraid that light conditions are changing during the test.
after i did the first three tests with the stouffer 120 6x6 I got following results -> see pictures
the steps 30/31 and 1/2 are missing because the stouffer wedge was displaced in the hasselblad filmholder :-(
- why I have this "jump" on step 16 to 16 (other side of the step-wedge).
- what do you think about those results in general?
- should I have to repeat the whole process or should i go on with minute 13,4 and 19,5 ?
Double-check your actual step wedge "calibration" densities.
I don't think the jump is that dramatic, but it's interesting.
When I drew a smooth dotted line between points, the "outlier" on the 9,75 curve was the point for Step 17.
I see your calibrated value for Step 17 is 1.60. The "outlier" "fell into line" when I changed that value to 1.61. So double-check, maybe your calibrated wedge is 1.61
I suggest checking centring. You also might want to use an enlarger lens with a longer focal length and raise the head some. An easy way to test uniformity is to expose a piece of film in your film-holder, with *no* Stouffer present. Then measure density at various locations across the negative.
thx,i used a step wedge-negative placing in the hasselblad filmholder, photographing a white card placing on zone X; did this with 5 films!
maybe the displacing of the negativ leads to an uneven illumination (i lost steps 30/31 and 1/2)
should i repeat shooting 5 films:blink: