In general, I think that sometimes the smaller incremental changes of a 51 step test strip interact poorly with the random variations in the paper and the inaccuracies of the rather inexpensive instruments we use to measure the test patches. With a well made profile to start with, a 21-step is usually enough and probably less prone to errors or unwanted artifacts in the final. It's also a way easier target to read and deal with.
I personally like to see a ramp next to the steps. A small glitch that is not seen by a 21-step is often visible as a vertical "line" in the smooth ramp.
I'd guess an averaged read set of something like 3-4 random 21-patterns is the best result for the work (if you use strip readers). See the targets Roy has in the QTR \bin folder.
Paul
On Wed, Oct 14, 2015 at 9:00 AM, David Lykes Keenan ausdlk@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
Anyone, anyone??I've been told that 21, 51, and 100-step charts worked with the app at one time with no problems.Is there a known problem with using measurements from a 51-step chart as input (with an associated .quad file) to input to the QTR-Linearize-Quad app?I'm using the i1PRO and i1Profiler software. I have no problem with 21-step measurement file as input but 51-step input fails with no error message or warnings. It worked once or twice, actually, but fails many more times than not.