August 30, 2022

Chlorargyrite from Tombstone, Arizona

From the 409 stope of the Empire Mine.
This is my specimen TT-22-11, an actual micromount from my collection.

I used the MPE-65 set at 5x and f/2.8. I set exposure to manual and 1/6 of a second.

Lighting is two Jansjo lamps with no diffuser. I turned room lights off and put a black cloth below the specimen. I set my color balance to 3600K.

I am using a 20 micron (0.020 mm) step size, which is 12 motor steps for my rail. I set the bottom focus to 101140 and the top to 101600, which yielded 40 exposures. I took a manual exposures to check things, then deleted it.

I had lightroom directly capture the images, which it saves as CR2 files. When it finished, I used Ctrl-A to select them all, then used the lightroom export to generate TIF files, putting them back into the same directory without resizing or renaming.

Now I go to my linux machine and start Zerene. I close my last project. I use File -- Add Files to bring the TIF files into Zerene. Once they were in, I use "Stack All, both" to do the stacking. The Dmap stack asks me to set the contrast threshold, and I use the slider to try to be sure it avoids a big deep out of focus hole.

The Dmap looks a lot nicer. On the Pmax, bright reflections from the chlorargyrite have stars and artifacts coming from them, and Dmap is much more tame. I do some retouching to get rid of a bright spot in the shadow area near the crytal. I commit the retouching, then I save the result directly to the 2022_minerals folder.

Next, I to to lightroom (back on the windows machine), find the final TIF image in the 2022_minerals folder and import it into lightroom.

I crop this a lot. It is not a terrific photo to be honest and that is all about the subject. I crop it to 1764 square. The original sensor height was 2592, so the field is now 3.74 * 1764/2592 = 2.54 mm. This might have been a better subject for the 10x Mitutoyo (The field with that lens is 1.87 mm tall).


Feedback? Questions? Drop me a line!

Tom's Computer Info / [email protected]