Developer concentration and developing times

<p>Hello,<br>

I've got a question....<br>

I want to develop a roll of Rollei retro 400s. I already did in rodinal 1:25 for 11 minutes. Results were good.<br>

<br />Now I'd like to try a different concentration of Rodinal. At 1:50 the suggested time is 22 minutes.<br>

Since I like rodinal at higher dilutions, I would like to know if at a ratio 1:75, 27.5 minutes would be adequate.<br>

Is there a way to determine developing times based on the developer concentration?</p>

<p>Thank you</p>

<p>35mm or 120?</p>

<p>Oh yeah sorry 35mm</p>

 

<p>I really love 1-100 with this film in a semi-stand. I pre-wash the film for 3 minutes in tap water then add the developer at 20C. I give an initial agitation of 30 seconds tap the tank and let it sit. I give it 2 inversions at 30 minutes. I drain stop and fix at 60 minutes.</p>

<p>supposedly iso 400 film is not well suited to rodinal.<br>

although modern films may work better using this developer.</p>

 

<p>supposedly iso 400 film is not well suited to rodinal.<br>

although modern films may work better using this developer.<br>

But if thre present dilution gives good results<br>

why change?<br>

also remeber that there must be sufficient developer<br>

in whatever solution you use to develop your film properly.<br>

If you have 350 or 500 ml of solution and half or less actual developer. the film may <br>

not be developed and thin negatives may be the result.<br>

stay with what seems to work well.</p>

 

<p>The Rollei 400S is not a normal ISO 400 film. It is an An Extended red Aerial film that works well in Rodinal like the 80S and 200 that Rollei puts out. It is made by Agfa Belgium. Some say the 400S is the same as the 200 but with a slight Push in the times but I can see by doing both that that is not true. </p>

<p>Thank you for the replies!</p>

<p>Ludwig,<br>

I use Rodinal and most commonly at the 1/50 dilution because I generally downrate film. I use a simple ratio, i.e. if I double the dilution, I double the time. I find this works very well when I am using Rodinal at 1/100 to compensate for reciprocity failure on long exposures. So, my advice would be to develop for 33 minutes.</p>

<p>Chris,<br>

next time I'll try the 33 minutes!</p>

<p>Thank you</p>

<p>OT, can rollei 400s be used as an infrared film with an appropriate filter?</p>

 

<p>It has been done Robert Vonk here on Pnet has the answers for this.</p>