What's the ratio of enlarging 4x5 to 8x10?

bobwysiwyg · May 15, 2009

Just curious about this one. If you take a 4x5 neg. and enlarge it to an 8x10 print, are you enlarging it 4X based on an area ratio or are you enlarging 2X based on linear measurements?

David A. Goldfarb · May 15, 2009

Generally in photography linear ratios are used for magnification and enlargement, so 4x5" to 8x10" is usually called a 2x enlargement. It might not always make sense to do it that way, and sometimes it's important to understand that the enlargement by area is different from the linear measurement, but that's how it's done.

Mick Fagan · May 15, 2009

The general consensus is a 4x5 neg enlarged to 8x10 is a two times enlargement factor.

In a darkroom, that is the way it is understood.

Mick.

bobwysiwyg · May 15, 2009

Thanks, actually, the linear approach always made more sense and is the way I have always thought about it. I recalled once seeing something to the contrary, i.e., referring to the area and it has bugged me since.

MattKing · May 15, 2009

Referring to the area does make sense if you are considering the issue of how the exposure needs to change (2 stops), but otherwise, the linear approach is better.

Matt

AgX · May 15, 2009

If one speaks of a 2x linear enlargement, how would you designate the respective area-ratio enlargement? Is there any adjective corresponding to `area-ratio´? Would you speak of a 4x `area-related´ enlargement?

Jeremy · May 15, 2009

bobwysiwyg said:
I recalled once seeing something to the contrary, i.e., referring to the area and it has bugged me since.

I find alt process printers refer to the increase in area much more often than linear enlargement scale as you have to measure your coating solutions by area covered, i.e. an 8" x 10" print takes 4x the solution a 4" x 5" print takes. Maybe the person who referred to area also does alt printing.

Mike Crawford · May 15, 2009

And what about the inverse square law? First thing we learnt at college!

jgjbowen · May 17, 2009

Maybe I can convince Kodak that my 8x10 film should only be twice the price of my 4x5 film :rolleyes:

What's the ratio of enlarging 4x5 to 8x10?

bobwysiwyg

David A. Goldfarb

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Mick Fagan

bobwysiwyg

MattKing

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AgX

Jeremy

Mike Crawford

jgjbowen

What's the ratio of enlarging 4x5 to 8x10?

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