Spectral sensitivity of RPX 25?

[Arcturus]

Does anyone know where I could find info about the characteristic curve and spectral sensitivity of the new RXP 25? I wasn't able t find any data on this film other than its dev chart. I shot a roll and it seems to have a very different spectral sensitivity than your average panchromatic film. A scene with purple flowers shot with Tri-X and no filter printed exactly as one would expect, a rather even set of tones. But the same scene shot with RPX 25 and no filter showed the flowers almost straight white. It almost had the look of IR film with a red filter. It seems to give more exposure to colors close to red than to others and in general renders tones differently than other similar films, like PanF and the old Efke25. Has anyone else had this experience, and do the other RPX films have this same effect?

 

[AgX]

about +/- 1 stop up to 700nm, then steep fall

 

[AgX]

http://www.macodirect.de/download/Rollei_RPX_25_dt.pdf

 

[Arcturus]

Thanks for that. It's interesting, not what I was expecting considering how differently it seemed to render certain colors. I guess more testing is in order!

 

[grommi]

And here the data sheet from the Agfa Aviphot Pan 40, an aerial film from Agfa Belgium. Obviously they are identical twins.
http://www.agfa.com/sp/global/en/binaries/AVI_PAN40_tcm611-57409.pdf

The old Maco game again. First they sold the aerial films RR 80s, Superpan200 = RR 400s (= IR400!) as an APX replacement, which of course was nonsense, now they sell another aerial film in the RPX series, which again is ..... you name it. Don't get me wrong, nothing against those aerial films, they are really nice. But they are no "regular" panchromatic films. The marketing was and is ..... you name it again..... I thought they might have learned something after the retirement of former CEO Schroeder, but I was wrong.

 

[miha]

Well, they don't look exactly identical to me: RMS and resolution differ.

 

[flavio81]

Well, they don't look exactly identical to me: RMS and resolution differ.

For the same film, the RMS number will vary with developer used, development used, target contrast index, and the density value that is measured.

Resolution will also depend in developer and development method.

Aerial films are usually intended to be processed with different developers and different contrast indexes (than pictorial films).

 

[Xmas]

But what you see a purple and trix and RPX sees can be different If you are using a triplet try

uV
yellow and then
red

filters.

If you were using a M8 then many black materials would be purple and you would need an IR cut filter...

 

[miha]

For the same film, the RMS number will vary with developer used, development used, target contrast index, and the density value that is measured.

Resolution will also depend in developer and development method.

Aerial films are usually intended to be processed with different developers and different contrast indexes (than pictorial films).

True, but have you seen the difference in resolution? 260 lines/mm for RPX vs 400 line pairs/mm for Aviphot, both at 1000:1

 

[flavio81]

True, but have you seen the difference in resolution? 260 lines/mm for RPX vs 400 line pairs/mm for Aviphot, both at 1000:1

Hmm...

The typical developer (D76 or ID11) has solvent action, i guess this ought to limit the max resolution. Also, for example, if you agitate too little, acutance effects improve sharpness but resolution theoricaly goes down. So it should depend on development method as well.

I'd speculate that 260 lines/mm is what you get with a standard developer, but with a special developer you would get more. The "400 line pairs" spec is by using the special G74c developer.

The spectral sensivity curves look identical!

 

[miha]

I don't think there is anything special about the G 74 c; it's a continuous tone high-speed developer. Well, this is speculation on my part, based on the limited data given.

 

[grommi]

Additionally the base of the large format sheets e.g. 4x5 is the same flabby one as the IR400s that falls into the bellows if you don't care for. Alls Agfa belgium films/sheets are made on the same thin PE base. So are the discussion results on the german Aphog board. Again, nice films if you want near IR sensitation in 135 and 120 format imho, e.g. I like the 400s very much. Very tricky in LF. But why did they call this film RPX 25? That's misleading. RPX 100/400 stand for traditional panchromatic, non tabular grain films like the old APX, made by Harman/Ilford on triacetate base. The 25 is superpanchromatic by Agfa Belgium on PE base. They don't have much in common.

 

[scheimfluger_77]

http://www.macodirect.de/download/Rollei_RPX_25_dt.pdf

Equally interesting is what's going on at the blue end of the curve.