The M.C.M Wedge Manufactured by Ilford Limited

The M.C.M Wedge came with a box of photographic bits and pieces from the auction site. It consists of graduated grey strips of cellulose graded from 1 (clear ) to 9 (black) sandwiched between two 4 inch glass plates.

 

It has a satin lined fitted case labelled M.C.M Wedge Manufactured by Ilford Limited. I wondered what it was for and was surprised to find a Google hit to the excellent Photomemorabilia website, with a PDF of Ilford News for Photographic Societies, Series 1 Number 5 of March 1939.

 

LINK --- https://www.photomemorabilia.co.uk/Ilford/Chronology/Ilford_News_Sr1No5_Mar39.pdf

 

It says "The M.C.M. Step Wedge has been designed by the editor of the Miniature Camera Magazine in collaboration with our Research Department as an aid to serious photographers who wish to classify papers by an accurate method of testing."

 

But, tantalisingly, "It is impossible to give full details here owing to space limitations, but readers will find a full description in the Miniature Camera Magazine for March." So - any ideas?

 

Edited February 5, 2021 by John Seaman

Reminds me of this - have one somewhere but couldn't find it. Link Vintage 1942 Kodak Projection Print Scale for Darkroom Printing | eBay

Edit: Basically a one step method of making test strips. Mine is a late '50's Model.

Edited February 5, 2021 by Sandy Vongries

That's interesting Sandy. The article talks about "to classify papers by an accurate method of testing". The Wedge has nine gradations, whereas the Print Scale has ten. It's tempting to compare these with the eleven zones of the Zone System, but I don't suppose there's a direct connection.

I assume it's the forerunner of the common 21 step tablet and would be used in a similar fashion. Hopefully they supplied the density of the steps.

Kodak made a similar printing 'wedge'. Except the kodak one was circular with segmented steps.

 

The Kodak one I have was designed to be laid on top of a small square of printing paper under the enlarger (with negative fitted and focussed up). It was then exposed for 60 seconds, and the time read off from the best exposed segment.

 

Its secondary use was for calibrating the contrast grade of papers. This was done by seeing how many steps were visible, from black to pure white.

 

I used it precisely once, to assess its usefulness.... it had none!

 

Your M.C.M wedge appears to be in one-stop steps, but it's not possible to assess the density accurately from what's shown.

Your M.C.M wedge appears to be in one-stop steps, but it's not possible to assess the density accurately from what's shown.

 

Yes, they are 1 stop apart, as near as I can tell. I put the wedge on a light box and measured the light values of the sectors using my Sekonic View Spot Meter L438, with the spot set at 4 degrees. The LV readings of the sectors were (sectors 8 and 9 weren't really readable):

 

1 - 12.6, 2 - 11.7, 3 - 10.8, 4 - 9.8, 5 - 8.5, 6 - 7.6, 7 - 6.7

The LV readings of the sectors were (sectors 8 and 9 weren't really readable):

 

1 - 12.6, 2 - 11.7, 3 - 10.8, 4 - 9.8, 5 - 8.5, 6 - 7.6, 7 - 6.7

That's about as good as you'll get with 1 stop exposure steps on a bit of film.

 

It's near impossible to develop exactly to a gamma of 1, and across several stops of exposure.

 

I found the indicated exposures with my Kodak segments to be quite a way off. I could have calibrated it, but I already had a neat little Philips enlarging meter sitting on the bench. So it went back into its little polythene sleeve and paper envelope, and disappeared into the 'odds & sods' drawer.

Kodak made a similar printing 'wedge'. Except the kodak one was circular with segmented steps.

 

 

 

Just as a sort of public service, for those inquiring minds, here is a little more data on the

Kodak Projection Print Scale, Publication R-26

 

Here is what the Kodak Black & White Darkroom DATAGUIDE (R-20) has to say about it

 

The KODAK Projection Print Scale , KODAK

Publication No. R-26, provides a convenient

method of making an exposure test. To make a

test with the print scale, place your negative in

the enlarger, focus it, and size the image. Then

place the print scale flat on the paper and

expose the paper for 1 minute. When the

paper is processed, pie-shaped segments of

different densities show numbers that represent

exposure times in seconds. The number

of seconds in the segment that has the correct

density is the exposure time you should use to

make your test print.

 

There are a few still for sale, some looking like new, old stock, on eBay = asking prices $10-20 US

Edited February 9, 2021 by JDMvW

There are a few still for sale, some looking like new, old stock, on eBay = asking prices $10-20 US

I'm hardly surprised that there are plenty of unused ones still around.

 

But 20 bucks?!

As a gift it would still be overpriced!:p

I'm hardly surprised that there are plenty of unused ones still around.

 

Kodak quasi-recognized that fact by providing the following information

 

The benefit of the Kodak Projection Print scale was that it read out with the needed expoiure

The benefit of the Kodak Projection Print scale was that it read out with the needed expoiure

Give or take a number of seconds!

That's interesting Sandy. The article talks about "to classify papers by an accurate method of testing". The Wedge has nine gradations, whereas the Print Scale has ten. It's tempting to compare these with the eleven zones of the Zone System, but I don't suppose there's a direct connection.

 

Well, an indirect connection. It is 10 zones as that is, more or less, what film can do, and also,

again more or less (probably less) what paper can do.

 

The Kodak Projection Print Scale that I have (present from my grandfather pretty early

after I started) goes from 2 to 48, so about 4.5 stops.

 

Not so obvious if a continuous or stepped scale is best.

hmmmmmm very informative discussion although I can just read, I know very little about darkroom processes. :)