What attributes to look for when enlarging negs.

Can anyone tell me the attributes to look for, when making a interpositive and

enlarged neg for both regular contact printing and for alt process printing, if

they are different. I'll be using 4x5 Delta 400 for the interpositive (just cause I

have it) and Bergger Orthochromatic BPFB-18 that I had bought in 8x10. I

don't have a densitometer to use, and I'll be using a cold light enlarger. I have

Xtol, ID11, D76 and Diafine for developers to choose from. Thanks

There are a few articles at Unblinking Eye which may prove helpful in making enlarged negatives.

Enlarged Negatives Using APHS Ortho Film and Pyro Developer

by Bob Herbst

http://unblinkingeye.com/Articles/EnlargeNeg/enlargeneg.html

and

Less is More - Negatives by Reversal

by Ed Buffaloe

http://unblinkingeye.com/Articles/NbyR/nbyr.html

I've had good luck with using a flat print as my interpositive. Haven't noticed any problems with the paper making any artifacts on the enlarged negative using Ilford MGIV in both RC and fiber. Since the ortho film will usually kick up the contrast, make sure you have good details in both the shadow and highlight regions of your interpositive.

Thanks for your note and time. I have read the articles mentioned and

searched the archives as well. It seems that of those that are doing this

process, all use different materials and processes not necessairly

translateable to what I am doing, per se'. Although I am using ortho as my

enlarged neg, I could just as easily use a slow film in 8x10, although the cost

would surely rise. I know that there are better methods as written about, and

better films, and developers to use such as Pyro, and maybe I'll get to them

one day, but for now I thought to work with what I have. The only mention that I

have read of using the more common materials such as mine, talk about

going for a denser interpositive and enlarged negative at one to 2 stops

darker. I guess what it comes down to is a matter of practice, so I'll start with a

denser interpositive and work from there.