Time difference for using a Jobo Drum?

[tom_aellis1]

<p>Good day.<br>

I know this has been posted before but I can't find it.<br>

I'm using a Jobo 2300 and while I do color with it I'm going to process b/w for the first time.<br>

I remember reading that I should minus Dev time off of the Film mfr receommend time.<br>

Was this 15 percent or 20 percent. Anything else?<br>

Thanks for your help.<br>

Tom</p>

[frank.schifano]

<p>Actually what you should do is check out Kodak's tech sheets. In them, you'll find processing times for small tank, large tank, tray, and rotary processing. If you work the numbers to find a percentage difference, you'll see that the time differences are more like around 10% less for rotary tube processing with continuous agitation (like a Jobo). Fine tune from there to suit your needs.</p>

[keith_tapscott]

<p>Tom, it is not a straight forward question to answer as there are so many different factors involved. Frank has made a good suggestion, depending whether you use Kodak B&W films and developers. The trouble is that there are so many different B&W film developers available and some are much more active than others, so there is no such thing as one factor applies to all.<br />Developers of the D-76/ID-11 and D-23 types are fairly low energy developers which may only need moderate correction. Weaker developers of the D-25 type like Microdol-X and Perceptol may need little or no correction. Higher energy developers like T-Max, T-Max RS will probably need a bit more correction and energetic, rapid acting developers like HC-110 and Ilfotec HC may require the most correction. This will also apply when using different processing temperatures, again different developer types may need more or less adjustment for different working temperatures.<br />T-Max, T-Max RS, Xtol, D-76/ID-11, DDX and Ultrafin Plus should be suitable for rotary processing. Read the technical data by the film/developer manufacturers for rotary processing and use that as a starting point.</p>

[nickc1]

<p>According to The Rotary Processor Manual by Jobo the following times are suggested:<br />Pan F ID11 (D76) Stock 6min<br />FP4+ ID11 (D76) stock 6min<br />Delta 400 ID11 (D76) stock 6min</p>

<p>As against the Ilford times of 6.5, 8.5 and 9.5 min respectively</p>

<p>ID 11 Diluted 1+1 Jobo suggested times are:</p>

<p>Pan F ID11 (D76) 1+1 8.5 min<br />FP4+ ID11 (D76) 1+1 8 min<br />Delta 400 ID11 (D76) 1+1 9 min</p>

<p>As against the Ilford times of 8.5, 11 and 14 min respectively</p>

<p>It is fairly obvious that there is no single factor that you can apply, except as a starting point to experiment from. One point that the Jobo manual is very insistent on is the need for a 5 min pre wash before developing to ensure even wetting of the film by the small quantity of developer used in a rotary processor.</p>

[keith_tapscott]

<p>Nick, I have that Jobo book by John Tinsley. Those times for FP4+ were from before the time Ilford invested in a new coating machine and switched to coating their emulsions onto a new film base. The old development times for FP4+ were then found to be too short, so you will need to read the latest Ilford technical publication for FP4+. Also, the Delta 400 mentioned in that book is for the old version while the latest Delta 400 is the 3rd generation version. Those times for Delta 400 don`t apply for the latest version.<br>

I suggest looking up the small-tank times and using those as a guide if a pre-rinse is used and reduce by around 5-10% if a dry pre-warm is used instead. You then need to see if the film contrast is OK, too much or too little and adjust the times from there.</p>

[dpbours]

<p>I use a Jobo autolab 800 rotary processor and as rule of thumb -15% of normal time.</p>

<p><em>Example Agfa APX100 35mm:</em><br>

Pre-wash 5 mins,<br>

then AM74 4mins 15 sec 1+7<br>

then X55 1m40 1+4<br>

then 3 mins last wash water<br>

1 mins rinse in H10.</p>

[profhlynnjones]

<p>Multiply the time by.85%, continuour agitation increases density by 15% to 20% so the development time must be slightly reduced.</p>

<p>Lynn</p>