Show HN: Rainbow – an attempt to display colour on a B&W monitor
31–40 of 61 posts
Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#32Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#33Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#34Can someone explains how this works? I have frustratingly been googling for 30 minutes now trying to learn how autochrome works. Being tech oriented it's so frustrating when people sum it up in 1 sentence "its made of potato starch and magically it makes color!" How does it work? Do they hand paint the screen? How does it actually add red or blue to an arbitrary shade of gray which lacks any chroma? Does it work with…
The trick is because the shade of grey DOES have chroma. You can't just apply any autochrome panel to the image (unlike what the OP is trying to do with Rainbow), instead, the negative is generated using the chrominance filter Imagine that each grain is blocking a 'pixel' of the negative. For simplicity of this explanation, I'll pretend the grains are red, green, and blue. If there's a blue grain, only blue light can…
I may be daft, and your explanation sounds reasonable but I still feel "magic + potato starch" :-D
Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#35This was actually a "thing" back in the 1950s. Apparently the results were awful: http://www.earlytelevision.org/color_filter.html
Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#36This was actually a "thing" back in the 1950s. Apparently the results were awful: http://www.earlytelevision.org/color_filter.html
They appear to just be green on the bottom, yellow in the middle, and blue on the top. Such that it might be plausible for outdoor scenery, but useless otherwise.
Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#37Earlier quoted context omitted.
Autochrome was an early technique for color photography. Wikipedia has a pretty good explanation [1]. The starch grains were randomly scattered on one side of the photographic plate, and acted as filters so that small portions of the plate would capture certain colors. The plate was then developed as a positive image. When you would shine light through the developed plate it would go through the starch grains (still…
> go through the starch grains (still on the plate) This part is key to understanding. The plate with the starch-based colored mosaic is not simply a filter used upon capture to be removed after (as most filters are today), but also a filter to be used upon viewing. Since the same exact “filter” is used for both capturing and viewing of a given photograph, it allows the mosaic to be random, simplifying creation of th…
Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#38Re: Show HN: Rainbow – an attempt to display colour on a B&W monitor
#39An aside: I saw "Up" (the movie excerpted in the demo video) years ago, but I never stopped and thought about the physics until today. The house would have started rising as soon as sufficient balloons were inflated inside the house. Releasing the balloons doesn't magically start making them buoyant-- they're already buoyant when they're inside the house.