A couple more Norma questions

**jonreid** · 3-May-2012, 02:57

Hi everyone,

There's no evidence of a missing fresnel on this one. I'll wash with soapy water. It really needs it, and pencil lines back on after.

Jon

**jonreid** · 3-May-2012, 04:13

Ok, I've just removed the ground glass and can see the 'seats' referred to above.

Next question might be really dumb. Forgive me if it is. The ground glass has two frames drawn on it, partially visible in the pics above. The inner frame has both 13x18 and 5x7 marked in it but measures only 112mm x 157mm. The outer frame is about 10 mm larger in each dimension.

I trust the entire glass area represents my image area. What are the frames? Conservative cropping guides?

Jon

**Frank Petronio** · 3-May-2012, 05:37

Hmm I don't know, I always figure I am going to clobber the edges so I always frame loose enough for my clumsiness. Never actually measured but I know 4x5 and 5x7 and 8x10 are not exactly that.

**jonreid** · 3-May-2012, 05:49

I think they must just be (very) conservative cropping guides for clumsy people like you Frank. Either that or they date from times when people avoided circles of confusion? The ground glass measures just under 5x7, about the same as my deardorff.

Since I'm mostly contact printing in platinum I tend to be fairly anal about the edges of the frame. I'll do some testing once I get a lens board sorted.

The black lines didn't end up washing off in soapy water anyway....

**Struan Gray** · 3-May-2012, 05:50

Film sizes are actually glass plate sizes. Some are exact, some are nominal, and there is some wiggle room. When sheet film came along it was originally sized to fit into adapter sheaths in a glass plate holder, so the film dimensions are smaller than the nominal size and the image area is smaller yet.

The actual sizes and image area are tabulated at various places around the web (perhaps even on this site), but there's an easier way. Put a filmholder in the camera and pull the darkslide facing you. You should be able to make out the edges of the film guides through the gg. That will tell you where the edges of your image are going to be.

**jose angel** · 3-May-2012, 06:12

What Struan says. Right now in my hands I have two holders, an old Graflex and a new Lisco... the Graflex lend a slightly bigger image. If you want accuracy, you have to draw the corners of your own holders.