sunlight vs.electronic flash for BW film speed tests

[wiedzmin]

Bill,

thank you for explaining it. I think I'm getting it.

So you can pick up a brick of unknown Tri-X, develop it "as much as possible"

Do you mean several tests or you just know it and can do it in one attempt?

[Bill Burk]

Bill,

thank you for explaining it. I think I'm getting it.


Do you mean several tests or you just know it and can do it in one attempt?

First time I always do a test of 5 developing times.

Test exposures on different sheets or few inches apart on roll film and cut them apart for different development times.

Later, as I go along, I just include a test exposure in with regular runs and "double check" what I was aiming for versus what I got.

[wiedzmin]

got it thank you

[wiedzmin]

I'm going to do tests using flash at full power to lower flash duration + gel to bring color temperature to 4500K. Film I'm going to test will be Fuji Neopan 100 Acros (120). I have 3 developers available xtol, hc-110, id-11. I 'm not sure which one I will use yet. Any suggestions are very welcome.

I will post results here early next week.

thank you very much for all input and help !

[wiedzmin]

This is result of my test. I finished last night.

film used: Fujifilm Neopan Acros 120
developer: HC-110 1+63
temperature 21 C
light source electronic flash Yongnuo YN-560 II with 1/4 CTO to convert to 4500K (attached pdf with flash power vs. flash duration test) - I used 1/125s shutter speed to photograph step tablet.

I have no previous experience with film testing - any advice, suggestions would be most welcome.

If test data looks all right I will do the last test to determine normal EI.

thank you
Tomasz

[PeterB]

That data appears fine Tomasz. You have a good portion of the toe for each curve which is something I failed to achieve during my film testing (I had to extrapolate the toe area on my 5 curves and enter 'dummy' data).

Peter

[wiedzmin]

thank you Peter,

I will use N development time from this test to perform the last test to determine normal EI.

Tomasz