Weston's enlarged negatives

[wilhelm]

If it was an 8.25" Verito on the Graflex, and if his Senica

viewcamera had a 30" bellows, he could just barely enlarge from

3.25x4.25 to 8x10. (30-8.25)/8.25 = 2.6 Reproduction ratio.

[david_clark4]

Hi again, in the back of volume I Mexico of The Daybooks of Edward

Weston, there is a piece by B. Newhall titled Edward Weston's

Technique. There Newhall writes, "To enlarge these negatives (B.N.

is refering to 3 1/4 * 4 1/4 Graflex negs.) on platinum or palladium

paper was tedious. An enlarged negative had to be made. First an 8*10

inch glass positive was made from a small negative. From this, in

turn, he made a new negative, which he printed by contact. Apparently

he never printed by projection..."

 

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Of course he doesn't give the method here for making the glass

positive. I guess some one has to come up with a list of reasonable

ways to make a glass positive. I assume there were holders where you

could use a glass negative in a regular 8*10 camera?

 

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Best, David

[wilhelm]

Paul Strand had the same problem since his originals (Before WWI)

were shot with a 6x9 Ensign. First he contact printed the negatives

onto Lantern Slide glass plates. (Apparently they didn't have

enlargers in those days, but they did have Lantern Slide

projectors.) Then, after retouching them, he PROJECTED the glass

lantern slide positives directly onto 8x10 or 11x15 film, which were

subsequently printed by daylight onto Platinum.

[david_clark4]

I don't know much about the math invovled in enlargement, but. I taped

a 4*5 neg to a light table. Using a 9 1/2 lens on a C1 I was able to

come very close to full 8*10 enlargement with the lens about a foot

from the neg and the bellows extended about 30". So, does anyone know

how you go about metering for such a shot? a magnification off a

light table that is. Best, David

[wilhelm]

David, a 9.5" lens with 30" bellows extension gives a reproduction

ratio of 2.16. (30-9.5)/9.5 = 2.16 large enough to easily make a 4x5

into an 8x10, but not enough for 3.25x4.25. To figure exposure, the

Effective aperture is just the marked aperture times the bellows

extension divided by the focal length. For example if you're

shooting at f:16 -- 16x30/9.5 = 50.5, or about f:50. Personally I

use a Horseman behind the lens meter so there's no worry about

extension or filter factors, etc. Don't forget to add in reciprocity.

[dk_thompson]

Well, when I've done this with a camera, it's been either 1:1 off a

4x5 or else the other way, 8x10 down to 4x5. Mostly I was making

internegs off CTs. With the 8x10s, I taped them to a sheet of white

plex, held it vertically, and backlit it with a speedotron head. It's

hard to take a meter reading off a ct this way, but one way to do it

is to appraoch it just like slide duping. Once you nail the exposure,

all images should be the same. You could use a wratten ND filter, 1.0

No. 96. This sort of approximates a gray card reading. I do this on a

slide duper, and it works well. What I mostly did was to average the

transmitted exposure, and test it on a polaroid. In some cases, I used

the 55 P/N for the interneg. Mind you, all this is just down & dirty

stuff, but it works.

 

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I avoid internegs like the plague though, I've always hated to make

them, but it's only been since we got a slide scanner that I've been

able to not do them so much.

 

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When I dupe negs, I do it by contact because the films are so slow.

They are about the speed of Azo. I usually just treat it like making a

print. But here again, once you get a system in place, you can group

negs in batches (density & contrast) and work them through. If you

used a regular film, like Plus-X or Delta 100 (seem to be 2 that are

recommended), you could shoot them off a light box, or just enlarge

onto them easily. It gets tricky when you try to filter out stains, or

make other corrections though. Kodak recommends using Tech Pan as the

interpositive, and TMX 100 as the working neg. I can't remember the

aim points right now, but you can use a densitometer to fine tune all

this, and a fairly accurate match of the original negative can be had

by someone who knew what they were doing.

 

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Back when labs used long roll contact printers (some still do), I

think enlarged negs were more commonplace. We still use a lab that

dupes up to 8x10 off our 4x5s for murals. I think they use a stat

camera with an illuminated baseboard for this though. I imagine that

would be the best for this sort of thing, makes me wish we hadn't of

surplused ours now....