Making a 6x9 frame on 4x5 GG

[Ari]

Hi,
Maybe I'm missing something here, but how would I make an accurate 6x9 frame on my 4x5 GG?
My LFPF & Google searches turned up nothing.
I have a Graflex 6x9 holder.

Thanks in advance.

[Drew Wiley]

I just took a bit of leftover Cibachrome paper, which is a tough dimensionally stable opaque polyester and sized it to fit rigth under the gg clips, then used an art knife to make
the exact 6x9 cutout.

[C. D. Keth]

I don't know exactly how your holder and camera back is designed. When I did this, I could remove the groundglass frame and set the rollfilm back in place backwards with the darkslide facing out. Then I just set the groundglass frame back into place the best it would go and just traced the outline of the opening. Once I had that done, I just touched up the lines a bit and that was that.

[RawheaD]

1. Take off your GG
2. Take a piece of aluminum foil and cover up the opening, make it flat, double it up for nice sturdy surface
3. Attach your roll film back, open the lid, take out the insert and dark slide
4. Mark the opening with a sharpie on the aluminum foil
5. Take roll film back off, attach your GG.
6. Mark GG :-)

84086
84087
84088

[Ari]

Thanks, guys.
Nice method, rawhead; pix and everything!

[wombat2go]

84096

[C. D. Keth]

Very nice, rawhead. That's a simple and elegant solution.

[Ari]

84096

Yes, but how did you arrive there?

[Ari]

1. Take off your GG
2. Take a piece of aluminum foil and cover up the opening, make it flat, double it up for nice sturdy surface
3. Attach your roll film back, open the lid, take out the insert and dark slide
4. Mark the opening with a sharpie on the aluminum foil
5. Take roll film back off, attach your GG.
6. Mark GG :-)

84086
84087
84088

Did it, works great, easy; thanks again.

[Emmanuel BIGLER]

For those who love precision, the actual size of a 6x9 image is about 56 by 82 mm, not 60x90 mm.
This depends on the rollfilm holder in use, sizes may vary by one or two millimeters around 56x82.

And for those who love to experiment with optics, a perfect centering of the frame can in principe be obtained by the auto-collimation method. A transparent frame is set on the ground glass, some source of light is used to illuminate the frame backward, and a small plane mirror is placed on the entrance side of the lens, perpendicular to the optical axis (i.e. on the edges of the filter mount).
A sharp image is reflected backward when the ground glass is exactly located in the focal plane, and any residual shift of the frame (or non-zero tilt setting, this is another story, so set your tilts to zero) results in an offset of the reflected image that can be detected easily.