HP5 and Perceptol

[arthur_nyc]

Hello All,

After reading the "Edge or Darkness" I would like to try perceptol. In the

book he gives a rec. of 1:2 for 11-13 minutes at a temp of 75f for HP5 EI200.

This is not a problem for me to try. My question is what would my time be for

HP5 at EI400 with the same dilution and temp? Also is there a good rule of

thumb to figure how to change times with an increase or decrease in the temp?

10%, 20% etc?

Thanks for your help

Arthur

[randall ellis]

Here is the data from the Massive Dev chart that I use as a starting point for this combination. I adjust film speed and development time based on the harshness of the light at the time of exposure, but you should do well getting started with these times.

<BR><BR>

Film Developer Dilution ISO 35mm 120 Sheet

<BR>HP5+ Perceptol stock 200-400 11 11 11 20C

<BR>HP5+ Perceptol 1+2 200 14.5 14.5 20C

<BR>HP5+ Perceptol 1+1 400 15 15 15 20C

<BR>HP5+ Perceptol 1+3 400 25 25 25 20C

<BR><BR>

- Randy

[kaiyen]

Compensating for temperature changes:

 

http://www.ilfordphoto.com/aboutilford/download.asp?n=430#search=%22ilford%20temperature%20compensation%22

 

print it out, laminate it, stick it to your wall. seriously.

 

Also, the reason why HP5 is recommended at 200 is because Perceptol tends to be a speed-decreasing developer. So 200 is about what you'll get out of it. If you're using perceptol, it probably don't make sense to essentially underexpose at 400. IMO.

 

allan

[robert_grasing]

Barry Thornton was certainly right about HP5+ in diluted Perceptol. Fine grain and very sharp. Straight Perceptol does cut film speed about a stop; however when diluted 1+2 or 1+3, it gives standard film speed (standard meaning what you would get in D76 or similar).

 

However, before you extend the developing time to get EI400, why not reread the captions for the photographs on pages 84-85? Thornton had good reasons for keeping it at EI200.

[chris_waller]

Try rating HP5 at 160 ASA and devving in Perceptol 1+3, 20 C, 13 minutes. Four inversions in the first 30 seconds than one inversion every 30 seconds after that.

[kirk_teetzel]

200 and 400 are processed with the same times.