Is Elke KB25 the same in 8x10 ?

[SteveKarr]

Hi everyone,
So I have some PL25 8x10 (which I've yet to shoot) and am in love with KB25 in 35mm.

So my question is ... are they the same stuff only slit & formatted different? I would love to use the 35mm or even 120 to test developers and stuff for the 8x10.

Hmmm...

Thanks~
Steve

[Drew Wiley]

Allegedly the same.

[Mark Woods]

Usually when the film is made, if I remember the Kodak process, it's 2 meters wide and as long as the base/liquid emulsion is. Once the emulsion is stable and can be handled, it is slit (cut). The emulsion is cut to whatever format is needed at the time. From what I see, Kodak runs a given amount of film based on orders and history. In the MP industry, one can get a significant discount when the film is ordered over a month in advance. It's prime cost when ordered in the week before. But a film will order between 60000 and 1million feet for a feature -- not a couple of boxes of 11x14 unfortunately. :-(

[Lachlan 717]

Wouldn't sheet film be significantly thicker than 35mm?

[Mark Woods]

To my knowledge, it's all the same. If you think about it, if the quantification of Dmin for a given emulsion is constant for different formats, then the base is constant. You may be right. If one did the calculation of $$/Sq. meter, one could quickly see if the LF shooters are paying more for their film than the MP productions. Motion Pictures are shot in color, so it might be difficult to find a MP B&W film cost base to evaluate.

[Oren Grad]

The Fotokemika website says the Efke 35mm, 120 and sheet films are coated on three different bases - 130 micron acetate for 35, 100 micron polyester for 120, and 175 micron polyester for sheet film. So they'd have to come from different coating runs. There might be minor variations in sensitometric behavior too.

[Lachlan 717]

To my knowledge, it's all the same. If you think about it, if the quantification of Dmin for a given emulsion is constant for different formats, then the base is constant. You may be right. If one did the calculation of $$/Sq. meter, one could quickly see if the LF shooters are paying more for their film than the MP productions. Motion Pictures are shot in color, so it might be difficult to find a MP B&W film cost base to evaluate.

Thanks, Mark.

The reason I asked is because I know some colour films are different in sheet v roll. For example, Provia is as follows*:

Base Thickness .....
Rolls-
135 : 127μm
120 : 104μm
220 : 104μm

Sheets: 205μm

*From Fuji's Provia Technical PDF

[Oren Grad]

I don't know of any emulsion that's coated on the same base for both sheet and roll variants. Kodak, Ilford and Fuji generally use acetate in different thicknesses for 35 and 120, and polyester for sheet films.

[Jim Fitzgerald]

Use the same developers. I've shot a lot of Efke 25 in 8x10 and love it. Take one holder and shoot two sheets and see what you get.

Jim

[Hovmod]

Yeah the sheets are thicker, but I use the same times and temps as 35/120 (4x5 only for me, though).

[mcfactor]

the 120mm base is much clearer than the 8x10 base. I was actually a bit disappointed by this. I dont feel that the 8x10 version of this has the same look as the 120mm, even though the emulsions are probably the same. The closest thing I have found is Adox Pan 25, which is the same (base and emulsion) as rollei pan 25. The base is completely clear.

[Drew Wiley]

120 film is conventionally on a thin acetate base, while sheet film is generally on thicker polyester. No difference in this case. A little bit of difference in base density
is easy to print through, especially given the great potential exposure range of this
particular film. I be more concerned about handling the fragile emulsion.

[Mark Woods]

I stand corrected. My experience is in the Motion Picture world where the 16mm, 35mm, and 65mm are all on the same base. The print films are a different story. Not knowing how the factory is set up, the same emulsion could be laid down on different bases on the same day. The emulsion machines are quite amazing!