TEST STRIP PROBLEM

[mike c]

Ok Dan, haven't tryed that,What do you do when making larger prints than your two mini's , re guess-timate or somehow calculate print exposer?

 

[dancqu]

Ok Dan, haven't tryed that,What do you do when making larger
prints than your two mini's , re guess-timate or somehow
calculate print exposer?

Going up from 3 1/2 x 5 to 5x7 calls for a near doubling of
the exposure. If one of the "minis" is close I add or subtract,
as the case may be, some little exposure from that near
doubling. IIRC, that is the same procedure used by
those making test strips.

Once THE correct exposure has been determined an enlarging
meter will nail it for larger or smaller prints. I've an Ilford
EM-10. Darkroom Automation offers a much more
refined unit. Dan

 

[mike c]

Thanks Dan,now it is more clear to me.I dont have a enlarging meter but plan to get one soon,probably form Dark room auto.herd some good things about their unit.See your point in printing the full neg for evaluating the print as a whole.

mike c.

 

[Brook Hill]

There is a formula for calculating the new time when changing the height of the enlarger head.

New time = (New length of projected image divided by original length of image) squared multiplied by the original time

Sorry for the long winded way of writing it but I can't write the formula in the normal way on my computer.

Tony

 

[mike c]

Well thats good to know,I'll write it down. thanks Tony.

mike c.

 

[Nicholas Lindan]

New time = (New length of projected image divided by original length of image) squared multiplied by the original time

Well, not quite ...

See the sticky thread on this subject at the head of this forum (there was a url link here which no longer exists)

 

[mike c]

I see,based on what math skills I have ,it seems the end result would be better calculated taken all things inconsideration by use of a enlarging meter(which so happens to be my plan any wise) thankyou Professor(Nicholas).

mike c.