Inkjet for digital negatives

[sanking]

Has anyone tried the comparison of say scanning an 8x10 negative and comparing say a Pt/Pd print or Azo or Carbon contact print to a print made via the digital negative?

Not 8X10, but I have made the comparison between original negatives and digital negatives in 5X7", 7X17" and 12X20" with all three processes.

Assuming perfectly exposed originals here is what I have found.


With AZO the original negative gives a better print when compared to a print made from a digital negative of the same size.

With carbon I still give a slight edge to the original negative when comparing prints of the same size, but slightly less of a difference than with AZO. But this advantage only goes for prints on smooth surfaces. On rough textured papers the image quality of prints made from original in-camera negative and from enlarged digital negatives, up to about 2X, is about the same.

With Pt./Pd. I can not tell any difference between a print made from the original negative and a digital negative, either with same size prints or with enlarged digital negatives of no more than about 2.5X.

To put this another way, in my opinion a 5X7", 7X17" or 12X20" AZO or carbon print from an original in-camera negative is superior to a print of the same size made from a digital negative.

With kallitype and Pt./Pd. there is little or no difference in image quality between a 12X20" print made with a digital negative from a 5X7" original and a print made from an original in-camera 12X20" negative, assuming digital negatives of no more than about 2X size of the original.

This is my opinion, and it is based on actually having made and examined quite a number of prints made with all of these processes using both in-camera and digital negatives. I have no interest in promoting either type of negative, just stating facts as I see them.

Sandy King

[sanking]

With kallitype and Pt./Pd. there is little or no difference in image quality between a 12X20" print made with a digital negative from a 5X7" original and a print made from an original in-camera 12X20" negative, assuming digital negatives of no more than about 2X size of the original.


Sandy King

I want to clairfy the above statement. All other things being equal (which is rare) print quality is determined by the amount of information, or detail, in the negative. Assuming the most optimum conditions of exposure an original 12X20" in-camera negatives will have a lot more information than a 5X7" negative. However, in typical landscape photography we rarely expose our negatives at an aperture that gives the highest resolution because depth of field considerations dictate otherwise.

In working with the 5X7" camera I rarely ever use a taking aperture of more than f/22. Assuming diffraction limiting resolution at about 1400/f-stop for white light the use of an aperture of f/32 results in a maximum possible resolution of about 63 lppm. Assuming magnification of about 2.5X to make a 12X20" print from this negative you get a maximum of about 25 lppm on the print. This is about 5 lppm beyond the limits of sight discrimination for most people at the optimum viewing distance of about 250 cm.

In the case of the 12X20 camera you need to close down the lens to at least f/64 in order to get an equivalent amount of depth of field to what you get with the 5X7 camera at f/22. This assumes of course that you enlarge the 5X7" negative 2.5X and make a contact print of the 12X20" negative. At f/64 the diffraction limiting resolution is 22 lppm. Many people expose most of their 12X20" negatives at f/90, which has a diffractin limiting resolution of 16 lppm.

There are many situations where it is possible to make exposures with both the 5X7" and the 12X20" camera at optimum aperture to produce maximum resolution. In these circumstances the 12X20" negatives is obviously going to have a lot more information, and if you print with a smooth silver gelatin paper this difference will be seen on the print. But it will probably not be seen on a kallitype or Pt./Pd. print, however, since the texture and paper fibers used with these processes limit resolution to 20 lppm or less.

Sandy