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1. Originally Posted by Bruce Osgood
When enlarging from 8X10 to 11X14 there is an ever-so slight reduction in contrast. I thought there was a problem with the math but the math is correct.

I'm not too concerned with this mystery as the results are generally quite pleasing.
That is because the physics of light is linear [predictable], while the chemistry of photography is non-linear [not totally predictable].

Steve

2. This evening I re-printed a photograph at a larger size. The previous print was 7x7" on 8x10 Ilford MGIV FB glossy. The exposure was for 9.5 sec. at f/16 at grade 3 1/2.

Tonight I printed the image up to 10x10" on 11x14 Ilford MGIV FB glossy. I had read this thread previously and instead of doubling the exposure, I just opened the lens up one stop (essentially the same thing). After a few test strips my final exposure was at 9.5 sec. at f/11 at grade 3 1/2... exactly one stop more exposure than the smaller print. Its funny how simple things are sometimes. But then I thought about it, the 7x7" print has 42 inches of area, and the 10x10" has 100 inches of area.. Approx. double.

I just wanted to add this for anyone, because this was an eye opener for me and will certainly give me a great starting point when re-printing from 8x10 to 11x14 (on MGIV anyway). No calculations or densitometer needed.

3. Spoilsport Brian, you know how we love our secret ways and calculations.

-TEX

4. Just curious, why do we have three page thread here when there is a "sticky" thread on the same topic?

5. Originally Posted by brian steinberger

But then I thought about it, the 7x7" print has 42 inches of area,
and the 10x10" has 100 inches of area.. Approx. double.
Although the larger print is close to 140% larger you found
that a 100% increase in exposure gave same results. How
do you account for that? In my experience that difference
of 40% is easily discernable. Dan

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