I've recently got my hands on a "23" 6x9 120 back for my Pacemaker, but have a little problem. There's no crop marks on my ground glass. What's the best method of determening where I should draw the crop marks?

Thanks, Magne

I assume your Pacemaker is a 4x5 (on a 2x3 the ground glass frame itself would show the image size). My suggestion is that you focus an image on the ground glass and make light pencil marks at the corners of the image. Then you can remove the ground glass frame from the back of the camera and go over the marks with a darker fine point pencil and straight edge. Also, I find it handy to put an "+" in the center of the image. If you're really ambitious you can measure off and draw grid lines at some convenient spacing, say 1 cm. I did this on my Century using a very fine lead drafting pencil.

I would install the roll holder, remove the insert and darkslide then mark the edges of the film gate or its corners.

Several dope slaps later, I realized that my suggestion won't work unless you do as 45PSS says and use the roll holder shell image cut-out ("film gate") as a template on the ground glass. The tricky part will be centering the shell and gate on the gg. A bit of trial-and-error with a ruler is in order.

Once I used opening of the roll-film holder as a template and pencilled the outline on the glass, I used some thin black border tape to make the outline more noticeable. The border tape is stuff that used to be used by newspaper & printing paste-up people to outline photos and put lines and borders around stories and advertisements. You can probably still find it at art supply shops.
Hope this helps!!!
Jack.

Member "Rangemaster" has a link posted that takes you to a site for satinsnow ground glass. Under the tab for downloads there is a link for downloading 4-4x5 ground glass templates that can be printed on transparency material. Two of the templates look like they will work with 120 roll film backs if they are cut down slightly. There are also 5x7 and 8x10 templates listed, as well. Does this help?