• Welcome to Photrio!
    Registration is fast and free. Join today to unlock search, see fewer ads, and access all forum features.
    Click here to sign up

Up-swept HD curve

polyglot

Member
Allowing Ads
Joined
Jun 12, 2009
Messages
3,467
Location
South Australia
Format
Medium Format
Efke IR820 has it in spades. Hurrell's film clearly had it. Older TXP apparently somewhat had it; current TXP in sheets may or may not still do it depending on who you ask.

Is there a film I can buy (I haven't tried R100/PL100 but the published curve is a lot straighter than for IR820) or processing technique that I can use to get a fairly long toe with a dramatic upsweep in the middle of the HD curve?

I've tried (semi-)stand development in Rodinal 1+100 and found that it gives the long toe but I also found that the compensation effect introduces significant shoulder so the highlights look quite dead. I want the curve to shoot up steeply as it goes through Zones VII-IX at least, without any apparently shouldering.

I can fake it easily by scanning, but obviously want to be able to do it with an all-analogue process.
 

john_s

Subscriber
Joined
Nov 19, 2002
Messages
2,211
Location
Melbourne, A
Format
Medium Format
HC-110 has a reputation for producing an upswept curve, according to

http://www.covingtoninnovations.com/hc110/

Ryuji Suzuki suggested TMax400 for this sort of curve. Maybe this pair is worth a try. Maybe box speed and generous development, not with a highly dilute developer? Just guessing.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
55,364
Location
Delta, BC Canada
Format
Medium Format
Somewhere here on this site there is discussion about using TMax 100 (I think) exposed at 200 and pushed to 400 ISO in HC110 to emulate TXP 320's upswept curve (IIRC).

No promises - I haven't tried it myself, and my memory certainly isn't perfect.
 

Thomas Bertilsson

Member
Joined
Jan 21, 2003
Messages
15,715
Location
Switzerland
Format
Multi Format
(there was a url link here which no longer exists)
 

brian steinberger

Member
Allowing Ads
Joined
Jan 5, 2007
Messages
3,055
Location
Pennsylvania
Format
Med. Format RF
If you're looking for an upswept curve from a panchromatic film that looks similar to IR820 I'm afraid you're just not gonna get it. Sure we can push films and overdevelop them but we're still not gonna get those glowing highlights you get with IR film, not to mention its very unique spectral sensitivity (vegetation goes white).

An upswept curve is something I've experimented with for quite a while. TMAX 400 pushed to 800 and developed in a speed increasing developer like Xtol 1:1 works ok, but lacks a bit too much shadow detail for me. Another combo that I've used to get a good upswept curve is Tri-x (TX, not TXP) in HC-110, especially pushed to EI 800.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
55,364
Location
Delta, BC Canada
Format
Medium Format
Thanks Michael and Thomas - good to know that my memory is almost accurate .
 

Thomas Bertilsson

Member
Joined
Jan 21, 2003
Messages
15,715
Location
Switzerland
Format
Multi Format
polyglot said:
Thanks, Thomas. Do you have any examples where it shows the very sparkly highlights (example with IR820) instead of flat lighting, and/or an HD plot?
Click to expand...

No. I don't. My photography life is mostly about shooting and very little about testing, so the example shown is the only one, and likely the only one I'll ever make.

- Thomas
 

ic-racer

Member
Joined
Feb 25, 2007
Messages
16,751
Location
USA
Format
Multi Format
I'm not sure why one would want a curve like that. The mid values will print too dark. This is one curve I got, with some combination of elements I won't use again
 

Thomas Bertilsson

Member
Joined
Jan 21, 2003
Messages
15,715
Location
Switzerland
Format
Multi Format
Low contrast lighting and portraiture, for two.

ic-racer said:
I'm not sure why one would want a curve like that. The mid values will print too dark. This is one curve I got, with some combination of elements I won't use again
Click to expand...
 

rmolson

Member
Allowing Ads
Joined
Feb 23, 2006
Messages
327
Location
Mansfield Oh
Format
Medium Format
Upswsept curve

Upswept curve


This may be bit off the topic but for years I bemoaned the loss of the old FP4 withD761:1 that would give me a bump in the straight line at the mid tone, lightening ever so slightly Zone V without affecting the highlights and shadows Present day FP-4+ while very good, doesn’t possess this quality. I had a densitometer and plotted curves in those days. over exposure and underdevelopment does not give the same result. It bends the full curve. We use to use that technique masking reflection copy in color separation. Not the same thing .On a the high end drum scanner we could do it as we had a five point scale to work with
 

Ryuji

Member
Allowing Ads
Joined
Jan 15, 2005
Messages
1,415
Location
Boston, MA
Format
Multi Format

Try Acros or T-MAX 400 in full strength film developer. You may have to overexpose because you won't get long toe.
Don't do semi-stand. Do Kodak agitation method every 30 sec or use continuous agitation.
If you are doing studio portrait like George Hurrell's classic headshots, it has a lot to do with lighting as well. Many portrait photographers today are not bold enough to use specular lights like his era. Put your softbox and shoot-thru's and switch to shiney metallic parabolic reflectors, especially the hair light. Be careful about the lens flare, especially if you use vintage lens. Any straight line film would be made to look reasonably darker midtone and harsh highlight like this... If the skin comes out too shiney/dewey use water based airbrush makeup and/or mattifying gel on the skin.
 

JaZ99

Member
Allowing Ads
Joined
Jan 6, 2009
Messages
68
Format
Medium Format
This is one of my first experiments with Acros, Rodinal, low temperature and minimal agitation:



The curve shape is very peculiar. Perhaps I need to repeat it.
 
You must log in or register to reply here.
Menu
Log in
Register