</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 13 2003, 10:44 AM)</td></tr><tr><td id='QUOTE'>BTW: you don&#39;t use control stripes to check whether your Tetenal or Jobo chemistry has finished, do you?</td></tr></table><span class='postcolor'>
I will run "test strips" (a.k.a. "control strips") EVERY time I start a color printing session. The ColorStar is "re-zeroed" according to the analysis of the test exposure. Shifts due to chemical changes (i.e. oxidation) are compensated by adjusting the color filtration.

The RA-4 chemicals I am familiar with have one distiguishing characteristic when they are oxidized out: the color developer will darken from a "light straw" to brown.
When I am in doubt, the test strip will be acid test: color balance will so far "out" as to be unobtainable, and Dmax will be lousy when the chemicals are beyond use.