My very first stack with zerene stacker (downloaded the trial yesterday).
Slides are a generous gift from Maria Inês, brazilian biologist, they were craft prepared in the 60's and are in remarkable condition.
17 images taken with Canon EOS utility using Canon 100mm macro and Raynox MSN-202 in front of it. iso 100, F/5, 1/500s Used fluorescent lamp behind the slide, but a very strong one
Combined with zerene stacker DMap method used percentile 18. Opened the final image in GIMP, set the white point, basic levels adjusment cleaning of dirt with brush tool and unsharp mask.
Heterodoxus longitarsus
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Beautifully done.
For images with a lot of uniform background, the "Percentile" number for the contrast threshold slider can be interpreted as the fraction of frame covered by background to be ignored. In this case, about 80% of the frame is background, so the Percentile might have been pushed much higher than 18%. Whether this helps or not depends on the subject. If the subject were deeper and you were having trouble with halo, a larger number like 75 might have helped to reduce the halo. In the case of this relatively thin slide, I suspect that halo was not much problem and even smaller Percentiles would have worked well. Did you try various values with this slide, and if so does my description match your experience?
--Rik
Edited to add: BTW, I posted an erroneous analysis a few minutes before this one. It was only up for a couple of minutes before I spotted the error and hastily deleted it, but if anyone saw the error, I apologize for any confusion.
For images with a lot of uniform background, the "Percentile" number for the contrast threshold slider can be interpreted as the fraction of frame covered by background to be ignored. In this case, about 80% of the frame is background, so the Percentile might have been pushed much higher than 18%. Whether this helps or not depends on the subject. If the subject were deeper and you were having trouble with halo, a larger number like 75 might have helped to reduce the halo. In the case of this relatively thin slide, I suspect that halo was not much problem and even smaller Percentiles would have worked well. Did you try various values with this slide, and if so does my description match your experience?
--Rik
Edited to add: BTW, I posted an erroneous analysis a few minutes before this one. It was only up for a couple of minutes before I spotted the error and hastily deleted it, but if anyone saw the error, I apologize for any confusion.