Lightroom is limited on color management

Adobe's Lightroom is really great. I now use LR for my 97% of time processing and printing photos. (The remaining 2% time uses Photoshop and 1% uses Silverfast).

However, LR is limited on color management and many times it causes annoying inconvenience:

(1) No soft proofing in LR's print module. For critical printing work, one has to open the file in Photoshop for soft proofing. My 16-bit color images scanned from 8x10 film are 1.5 GB and opening them in both LR and PS can be really slow, if not crashing my computer.

(2) The rendering color profile used in LR's Develop module is ProPhoto RGB but in Library and Print module it is Adobe RGB (1998). Because of this, I have seen some color inconsistency when the image is seen at different LR modules. For example, some deep reds cannot be shown in Adobe RGB color space.

I guess Adobe does not want LR to reduce too much users from PS so they purposely make the LR imperfect... sigh.

A Zemax Case

I had a design using a prism pair to circularize laser diode's elliptical beam. The theoretical plot is below:



The prism positions are designed for 488nm, wavelengths deviating from 488nm will have some beam walk-off (both displacement and steering). Now I want to know how much I need to twist the prism pair for correcting the beam walk-off. The pivot point of twisting is a pin at somewhere not far from the prisms. (Twist the two prisms together since this is a sub-assembly).

To simulate it in Zemax, I first draw the prisms in SolidWorks with the pivot pin:



Note that in SolidWorks I make the origin point at the pin location. Then I Save As the model in IGS format, to folder C:\Program Files\ZEMAX\Objects\CAD Files. After Zemax imports this file, the reference point is at the pin, which is what I wanted. I found that saving as STL file won't keep the reference point at the same location as in SolidWorks.

Below is the Zemax screen capture. It is a non-sequential model. I can rotate two prisms together around the pin location in Zemax. Beam compression, displacement and steering can all be checked. (Click on images to see in full size.)

Basic of basics of polarization and reflection.

Once upon a time these were taught in college; but I need to refresh them in my mind every once in a while.

p and s polarization: (forget about their Greek/German/? equivalent) Here p means "plunge", s means "stick". Because p light is easier to penetrate (plunge into water) whereas s light is easier to be reflected (a stick bounced from water).

At Brewster angle, the reflected beam is purely s-polarized, meaning the p-polarized light has zero reflectance. Wikipedia [1] has an excellent image to show this effect:



Reflectance vs incident angle is below (for 532nm and fused silica):

At Brewster angle (~56^o), reflectance of s-polarization is about 14%.

References and notes
[1] http://en.wikipedia.org/wiki/Polarizer