by Joe Farina » Wed Dec 21, 2022 1:08 pm
For those of us who have a Sapphire 488 (which has become a fairly common and inexpensive surplus blue laser), I've found a blue pigment which reflects an excellent blue color (similar to the appearance of a clear blue sky) when illuminated with 488nm: Cobalt Blue.
I tried a number of other blues under 488nm, and this seems best.
Also, I got my three beams together (532, 633, and 488) and looked at some random color objects with blues, and as expected, the blue color rendition was terrible. So, if someone is trying to do color holograms of "found objects" then 488 is definitely not the way to go, being close to the border of blue and green. However, if the objects are being painted by the holographer, and Cobalt Blue is an acceptable choice for blue, the outlook is promising. Also, with 488nm, I would expect less scattering noise (from whatever source) compared to 457nm.
I should note that a casein binder for the paint is preferable (link below) for my long exposures (in contrast to a gum arabic binder such as found in watercolor and gouache) since gum arabic appears to grab moisture from the air and "crawl" on the surface of the object.
https://www.jerrysartarama.com/richeson ... 2cEALw_wcB
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For those of us who have a Sapphire 488 (which has become a fairly common and inexpensive surplus blue laser), I've found a blue pigment which reflects an excellent blue color (similar to the appearance of a clear blue sky) when illuminated with 488nm: Cobalt Blue.
I tried a number of other blues under 488nm, and this seems best.
Also, I got my three beams together (532, 633, and 488) and looked at some random color objects with blues, and as expected, the blue color rendition was terrible. So, if someone is trying to do color holograms of "found objects" then 488 is definitely not the way to go, being close to the border of blue and green. However, if the objects are being painted by the holographer, and Cobalt Blue is an acceptable choice for blue, the outlook is promising. Also, with 488nm, I would expect less scattering noise (from whatever source) compared to 457nm.
I should note that a casein binder for the paint is preferable (link below) for my long exposures (in contrast to a gum arabic binder such as found in watercolor and gouache) since gum arabic appears to grab moisture from the air and "crawl" on the surface of the object.
https://www.jerrysartarama.com/richeson-casein-artist-colors-cobalt-blue-37-ml-05056?gclid=Cj0KCQiA-oqdBhDfARIsAO0TrGGAOPmUeWJJNIVQDu69J23lz6qqPuyOEbVj3JfWzqTJIOaUYxcwVSkaAi2cEALw_wcB