Omega Glass Negative Carriers: Loss of Contrast?

[Huram]

I recently purchased a 4x5 Omega Glass Rapid Shift Carrier.

I did some 6x6 neg B&W printing last night. For the first session, I used my glassless 6x6 negative carrier. For the second session, I used my 4x5 glass negative carrier -- same 6x6 negative, same amount of time. I noticed that the prints with the glass carrier lost a significant amount of contrast. Anyone else experience this?

It was not developer exhaustion, cause I went back and used the glassless neg, and found that the prints had the same contrast. The negative was quite flat with both carriers. I am guessing the glass was the culprit in the loss of contrast, although maybe the extra light from the 4x5 space had something to do with it?

Any thoughts on what is causing this?

Remedies? Just up a filter grade? (I use VC paper) What is a good way to make a mask when using your 4x5 glass carrier for 6x6 negs?

I am pretty sure that both the top and bottom glass on this Omega Carrier is the original. Does any one know if the Omega glass is the anti-newton stuff?

Thanks for the help.

Dave

 

[Will S]

Maybe you need to mask the 6x6 negative?

 

[David A. Goldfarb]

I agree. Try masking the negative to reduce light spillover.

 

[Bob Carnie]

Agree with the above, must mask off to the rebate or you will indeed lower contrast with spill light.
Propery masked you will not have a loss of contrast using glass carrier.

 

[Huram]

What is the best way to mask using this Rapid Shift carrier? Just slide some thin cards on either side of the Neg in the carrier sandwich? Take a thin piece of opaque material and make a 6x6 window to put in the carrier sandwich? Thoughts would be greatly appreciated.