8 ms·

Show HN: Paint Color Matching App (Sherwin, Behr, PPG)

48 points by jhiggins777 7y ago

rkho 7y ago
Oh this is fun. I recently paid $4.99 to unlock similar functionality with a different webapp, though that one also supported Kelly Moore and others. Any intentions on adding suggested palettes?
rafamvc 7y ago
This doesn't have all Sherwin Williams colors. And the dropdown stops at the letter B and after.
- jhiggins777 7y ago
  Oh shoot, thanks for letting me know. I'll fix that.
- jhiggins777 7y ago
  The app actually does have all Sherwin Colors, they are just not all in the dropdown (you can search for them). I added all of them in the dropdown for now in a really janky way. I'll do a proper design in the next few days.
ghostbrainalpha 7y ago
What I want the ability to upload a picture of a paint chip, AND tell you how long it has been since that wall was painted. That way the app could adjust for fading and tell me what color that paint was originally.
- tdy721 7y ago
  It's more variable than just time; and really if you aren't matching the color, just pick one you like?
crazygringo 7y ago
I'm curious... if the RGB values are all accurate, is there a standard color and exposure calibration for paint swatches that is shared across brands? The white point (color temperature) is easy, using whatever light source they're being illuminated with. But what determines whether a particular white is (240, 240, 240) or (250, 250, 250) or (255, 255, 255)? The exposure seems far more arbitrary. Is there some kind of maximally bright matte "reference white" material photographed next to each swatch, that then gets calibrated to (255, 255, 255) or similar? If so, it would be pretty cool if you could buy a reference white chip like that, hold it up to a painted wall in your house, and have an app that could take a photo with both and output the "true" current paint color.
- cmurf 7y ago
  The frontend you see is RGB due to the internet and the display you're using. But on the backend (the manufacturer's system, no idea what the web site employs) the color science is all in spectral data. The xyz color matching functions [1] can be used to determine human response to that spectra, and then to 'CIE L* a* b*' for unambiguously referring to the color. The typical white in the paint industry is CIE illuminant D65. You're right to wonder about "what is white" which gets into topics of 'chromatic adaptation', 'color constancy', and 'discounting the illuminant'. If you get a perfectly diffuse white tile, what color is it when illuminant by incandescent versus fluorescent? And there are more than a few CIE F illuminants, and more proprietary ones. And hence each application tends to standardize on, and thus assume, an illuminant. You can use some other illuminant if you want, but then you're in custom territory and it wouldn't surprise me if some companies are doing that, secret sauce. In special cases like automotive and textiles, it's common to see multiple spectral values due to different colors at different angles, and thus spectrogoniometry. [1] https://en.wikipedia.org/wiki/CIE_1931_color_space https://en.wikipedia.org/wiki/CIE_1931_color_space
- colanderman 7y ago
  You are thinking of a grey card: https://en.wikipedia.org/wiki/Gray_card https://en.wikipedia.org/wiki/Gray_card However color matching is more complex than that. "Color of the light source" varies considerably, not only due to the illuminant itself, but also the materials the illuminant is reflecting off of (e.g. walls). And color temperature only defines black bodies, which most light sources are not: you need information about the full spectrum of the illuminant to determine how it interacts with the material to be color-matched. This is getting a bit into metamerism: https://en.wikipedia.org/wiki/Metamerism_(color) https://en.wikipedia.org/wiki/Metamerism_(color) (Of course, paint cannot match an arbitrary spectrum. Matching under specific lighting conditions is the least you can hope for.) And the above is considering color of a surface only as a scalar value, but it's really a function of illumination angle as well, due to gloss. Direct lighting on a glossy surface reflects more of the color of the gloss, whereas oblique lighting reflects than the paint itself. Diffuse lighting is some combination thereof. (I am not a color scientist by any means, just interested in the topic. Experts please correct!)
pkaye 7y ago
I got one of those Color Muse color matching devices and this matching gets hard when you have glossy or rough surfaces. I've been trying to get some touchup paint to cover a stucco patch and despite many attempts, never can match it close. The colors look different at various angles.
- lttlrck 7y ago
  I have the same problem. My current plan is to illuminate a patch from many angles to eliminate all the shadows. Add a reference white or gray card. Take a photo then in GIMP, adjust the white point, blur the stucco, read off the RGB and look up the closest matching color code. I have yet to find a way to look up by RGB. If it somehow works I’ll avoid having to paint the whole house.
  - joshyeager 7y ago
    Your best bet is to cut a piece of paint off the wall and take it to a paint store. They probably won’t be able to match it exactly, but it’ll be closer than you can do in RGB.
  - catblast 7y ago
    If you’re concerned about a close match, this is unlikely to give satisfactory results. Take your samples to a good paint store. Those machines are more sophisticated then you may think.
  - mceachen 7y ago
    The colorimeter at your local paint store, looking at a paint chip from your wall, is very likely going to do a whole lot better than the process you just described. If you call the store, ask how big of a paint chip sample they need to match existing, weathered paint. It very well may be tiny (like, 1cm^2), and they should do this color match for free. You could buy just a pint, first, to see that it works. I've been quite surprised by how non-uniform most digital camera imagers and in-body post processing color pipelines muck with the spectrum coming off the sensor, all in the name of producing a more pleasing JPEG. If you still want to do what you described, I'd use RAW and use dcraw to convert to tiff, and open that in gimp.
lttlrck 7y ago
I would love to be able to match by RGB. Edit: actually it’s almost possible to do what I need. It’s just be much easier if it was possible to find closest match. Still this could be helpful.
- andytruett 7y ago
  I've used the following to match RGB and HTML color codes to paint colors: http://www.easyrgb.com/en/match.php http://www.easyrgb.com/en/match.php. Wasn't perfect, but got me pretty close!
mjgoeke 7y ago
Something is off. The matched colors show an RGB with each, but it's the same value when the color is obviously different. I took a screenshot of it and pulled it up in an image editor to make sure. e.g. https://www.matchmypaintcolor.com/ppg/medieval-forest https://www.matchmypaintcolor.com/ppg/medieval-forest shows RGB 1,116,120 for all 3 swatches, but only the Maxi Teal is that RGB, the other tiles have other RGB values.
- jhiggins777 7y ago
  Thanks mjgoeke, all fixed.
swframe2 7y ago
I'm curious. What is the algorithm to determine how to mix paints to match a color?
- jhiggins777 7y ago
  https://github.com/dtao/nearest-color https://github.com/dtao/nearest-color
jamesrom 7y ago
How do you calculate the distance between these colors? RGB distance will be close enough, probably, but for matching paint/ink in the real world, it's important to consider visual (sensation) difference. https://en.wikipedia.org/wiki/Color_difference https://en.wikipedia.org/wiki/Color_difference
- jhiggins777 7y ago
  https://github.com/dtao/nearest-color https://github.com/dtao/nearest-color
markdown 7y ago
> PPG, Behr, & Sherwin Williams What are these? The website doesn't seem to explain anywhere.
- jhiggins777 7y ago
  The major paint manufacturers.
  - markdown 7y ago
    Ahh ok, thanks. Must be American. Never heard of them in my part of the world.
bradknowles 7y ago
I have a Pantone CapSure color sampling/matching device, which includes a wide variety of color samples from various manufacturers. Any idea how this process compares?
kube-system 7y ago
I need this but for automotive paints
gitgud 7y ago
This looks exactly like one of those "Buy this domain" place holder sites. Compare the pair: - https://www.matchmypaintcolor.com/ https://www.matchmypaintcolor.com/ (this site) - http://surfweb.com/ http://surfweb.com/ (fake site)

48 points by jhiggins777 7y ago

rkho 7y ago

Oh this is fun. I recently paid $4.99 to unlock similar functionality with a different webapp, though that one also supported Kelly Moore and others. Any intentions on adding suggested palettes?

rafamvc 7y ago

This doesn't have all Sherwin Williams colors. And the dropdown stops at the letter B and after.

jhiggins777 7y ago
Oh shoot, thanks for letting me know. I'll fix that.
jhiggins777 7y ago
The app actually does have all Sherwin Colors, they are just not all in the dropdown (you can search for them). I added all of them in the dropdown for now in a really janky way. I'll do a proper design in the next few days.

ghostbrainalpha 7y ago

What I want the ability to upload a picture of a paint chip, AND tell you how long it has been since that wall was painted. That way the app could adjust for fading and tell me what color that paint was originally.

tdy721 7y ago
It's more variable than just time; and really if you aren't matching the color, just pick one you like?

crazygringo 7y ago

I'm curious... if the RGB values are all accurate, is there a standard color and exposure calibration for paint swatches that is shared across brands? The white point (color temperature) is easy, using whatever light source they're being illuminated with. But what determines whether a particular white is (240, 240, 240) or (250, 250, 250) or (255, 255, 255)? The exposure seems far more arbitrary. Is there some kind of maximally bright matte "reference white" material photographed next to each swatch, that then gets calibrated to (255, 255, 255) or similar? If so, it would be pretty cool if you could buy a reference white chip like that, hold it up to a painted wall in your house, and have an app that could take a photo with both and output the "true" current paint color.

cmurf 7y ago
The frontend you see is RGB due to the internet and the display you're using. But on the backend (the manufacturer's system, no idea what the web site employs) the color science is all in spectral data. The xyz color matching functions [1] can be used to determine human response to that spectra, and then to 'CIE L* a* b*' for unambiguously referring to the color. The typical white in the paint industry is CIE illuminant D65. You're right to wonder about "what is white" which gets into topics of 'chromatic adaptation', 'color constancy', and 'discounting the illuminant'. If you get a perfectly diffuse white tile, what color is it when illuminant by incandescent versus fluorescent? And there are more than a few CIE F illuminants, and more proprietary ones. And hence each application tends to standardize on, and thus assume, an illuminant. You can use some other illuminant if you want, but then you're in custom territory and it wouldn't surprise me if some companies are doing that, secret sauce. In special cases like automotive and textiles, it's common to see multiple spectral values due to different colors at different angles, and thus spectrogoniometry. [1] https://en.wikipedia.org/wiki/CIE_1931_color_space https://en.wikipedia.org/wiki/CIE_1931_color_space
colanderman 7y ago
You are thinking of a grey card: https://en.wikipedia.org/wiki/Gray_card https://en.wikipedia.org/wiki/Gray_card However color matching is more complex than that. "Color of the light source" varies considerably, not only due to the illuminant itself, but also the materials the illuminant is reflecting off of (e.g. walls). And color temperature only defines black bodies, which most light sources are not: you need information about the full spectrum of the illuminant to determine how it interacts with the material to be color-matched. This is getting a bit into metamerism: https://en.wikipedia.org/wiki/Metamerism_(color) https://en.wikipedia.org/wiki/Metamerism_(color) (Of course, paint cannot match an arbitrary spectrum. Matching under specific lighting conditions is the least you can hope for.) And the above is considering color of a surface only as a scalar value, but it's really a function of illumination angle as well, due to gloss. Direct lighting on a glossy surface reflects more of the color of the gloss, whereas oblique lighting reflects than the paint itself. Diffuse lighting is some combination thereof. (I am not a color scientist by any means, just interested in the topic. Experts please correct!)

pkaye 7y ago

I got one of those Color Muse color matching devices and this matching gets hard when you have glossy or rough surfaces. I've been trying to get some touchup paint to cover a stucco patch and despite many attempts, never can match it close. The colors look different at various angles.

lttlrck 7y ago
I have the same problem. My current plan is to illuminate a patch from many angles to eliminate all the shadows. Add a reference white or gray card. Take a photo then in GIMP, adjust the white point, blur the stucco, read off the RGB and look up the closest matching color code. I have yet to find a way to look up by RGB. If it somehow works I’ll avoid having to paint the whole house.
- joshyeager 7y ago
  Your best bet is to cut a piece of paint off the wall and take it to a paint store. They probably won’t be able to match it exactly, but it’ll be closer than you can do in RGB.
- catblast 7y ago
  If you’re concerned about a close match, this is unlikely to give satisfactory results. Take your samples to a good paint store. Those machines are more sophisticated then you may think.
- mceachen 7y ago
  The colorimeter at your local paint store, looking at a paint chip from your wall, is very likely going to do a whole lot better than the process you just described. If you call the store, ask how big of a paint chip sample they need to match existing, weathered paint. It very well may be tiny (like, 1cm^2), and they should do this color match for free. You could buy just a pint, first, to see that it works. I've been quite surprised by how non-uniform most digital camera imagers and in-body post processing color pipelines muck with the spectrum coming off the sensor, all in the name of producing a more pleasing JPEG. If you still want to do what you described, I'd use RAW and use dcraw to convert to tiff, and open that in gimp.

lttlrck 7y ago

I would love to be able to match by RGB. Edit: actually it’s almost possible to do what I need. It’s just be much easier if it was possible to find closest match. Still this could be helpful.

andytruett 7y ago
I've used the following to match RGB and HTML color codes to paint colors: http://www.easyrgb.com/en/match.php http://www.easyrgb.com/en/match.php. Wasn't perfect, but got me pretty close!

mjgoeke 7y ago

Something is off. The matched colors show an RGB with each, but it's the same value when the color is obviously different. I took a screenshot of it and pulled it up in an image editor to make sure. e.g. https://www.matchmypaintcolor.com/ppg/medieval-forest https://www.matchmypaintcolor.com/ppg/medieval-forest shows RGB 1,116,120 for all 3 swatches, but only the Maxi Teal is that RGB, the other tiles have other RGB values.

jhiggins777 7y ago
Thanks mjgoeke, all fixed.

swframe2 7y ago

I'm curious. What is the algorithm to determine how to mix paints to match a color?

jhiggins777 7y ago
https://github.com/dtao/nearest-color https://github.com/dtao/nearest-color

jamesrom 7y ago

How do you calculate the distance between these colors? RGB distance will be close enough, probably, but for matching paint/ink in the real world, it's important to consider visual (sensation) difference. https://en.wikipedia.org/wiki/Color_difference https://en.wikipedia.org/wiki/Color_difference

jhiggins777 7y ago
https://github.com/dtao/nearest-color https://github.com/dtao/nearest-color

markdown 7y ago

> PPG, Behr, & Sherwin Williams What are these? The website doesn't seem to explain anywhere.

jhiggins777 7y ago
The major paint manufacturers.
- markdown 7y ago
  Ahh ok, thanks. Must be American. Never heard of them in my part of the world.

bradknowles 7y ago

I have a Pantone CapSure color sampling/matching device, which includes a wide variety of color samples from various manufacturers. Any idea how this process compares?

kube-system 7y ago

I need this but for automotive paints

gitgud 7y ago

This looks exactly like one of those "Buy this domain" place holder sites. Compare the pair: - https://www.matchmypaintcolor.com/ https://www.matchmypaintcolor.com/ (this site) - http://surfweb.com/ http://surfweb.com/ (fake site)