xiphmont: (Default)

Most makers I know keep a bunch of paint colors around.

Me, I have a few primaries and maybe 40 different whites. Nothing messes with me like THE WRONG WHITE. And yes, I *do* own a handheld spectrophotometer! Why do you ask?

I need to paint my new control panel with a good match to the other panels, so I got out my paint test strips. It's hard to tell, but there are five different white stripes on the particular pictured strip.

Anyway, we have a winner! Spectrophotometer agrees! The laser cutter's white matches Duplicolor 'Toyota White'.

xiphmont: (Default)

The little handheld spectrometer I've been using for LED and color matching work, aside from being something of a toy, is intended for lighting applications, that is, for very bright light (e.g., it's rated to be pointed directly into the sun) with a wide field of view. Screen evaluation requires low light sensitivity in a narrow field.

Sometimes two pounds of optical glass is easier and cheaper* than the 'right' tool.

*$19 for two 3" condenser lenses from Anchor Optics. Anchor is awesome.

xiphmont: (Default)

...measure with ruler, mark with Sharpie, cut with utility knife, assemble using foamboard and hot glue.

xiphmont: (Default)

There are so many posts that need to come out of this one...

I ordered a whole bunch of Chinese LED conversion kits. I tried lots of ways to mod them to work on Thinkpads, all of which worked... though many turn out not to work well enough, so don't use the mods on those pages for now :-(

Dissatisfied with all offerings, I designed and have been testing my own LED driver boards....

The LED strips that came with the Chinese kits all had terrible color rendering (low temperature, greenish, or both) on the spiffy AFFS screens the X61T is known for.

...so that's sucked me into the world of spectrometers, reverse engineering the protocols to use them on Linux (oh, yeah, I need to publish that), binning leds by hand with a makeshift integration chamber...

...and then of course all the software needed to take the SPD data from the assembled system and interpret the color data, then plot it, which I just finished today!

That contrast measurement is too low and I know why, the sensor is too close and unbaffled, so it's picking up IPS glow. Time for measurement jig rev 2....


xiphmont: (Default)


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