Changing colours mathematically
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Changing colours mathematically
15-01-2020 10:54 AM
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How would the photobrains set about this? Is it possible?
I have identified with the colour picker the rendered colourcodeof an object as RGB 52 60 33. The true RGB code is 123 249 247. The slide on each colour on the channel mixer is set to its max 100.
Does anyone know how to use the sliders on the mixer to adjust from seen to real colour, seeing as colours are scaled in HEX, but the slider in DEC?
Re: Changing colours mathematically
15-01-2020 11:19 AM
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@Luzern Where are you getting this information from? There is a huge difference in value (and therefore colour) of the two RGB values you quote.
Re: Changing colours mathematically
15-01-2020 2:21 PM - edited 15-01-2020 2:25 PM
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@Luzern wrote:
I have identified with the colour picker the rendered colourcodeof an object as RGB 52 60 33. The true RGB code is 123 249 247. The slide on each colour on the channel mixer is set to its max 100.
Does anyone know how to use the sliders on the mixer to adjust from seen to real colour, seeing as colours are scaled in HEX, but the slider in DEC?
It's unusual to quote individual components in hex - but you might quote a colour as e.g. #FA89FF.
123 decimal = 7B hex
249 decimal = F9 hex
247 decimal = F7 hex
So your "true" colour could be written as #7BF9F7
Weird program you are using...
"In The Beginning Was The Word, And The Word Was Aardvark."
Re: Changing colours mathematically
15-01-2020 2:52 PM - edited 15-01-2020 2:52 PM
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The colour codes give colours which are a long way apart - see attached.
The top row of digits are decimal, the borttom row are the hex equivalents. The two colors you mention are at the extremes.
Are you sure the colour picker is getting the colour you want. many colours on screen are "dithered" with adjacent pixels being different colours to give the shade desired. Try the colour picker on different pixels in the same area.
What program are you using?
Re: Changing colours mathematically
15-01-2020 4:38 PM
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I'll come back later once I have another photo that is true colour for an element in the one I am playing with.
Re: Changing colours mathematically
15-01-2020 11:51 PM
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It seems the other info is not available.
I manage to type the values I got from the colour picker wrongly, but by as little as 2 under what was intended in one of the figures.
Yes I agree that there is a vast difference in the values from the picker, but I got the code for the true colour from https://rgbcolorcode.com/color/electric-blue The colours of the photo are indeed up the creek.
My program is Photoplus X7 that is not too dissimilar from Photshop.
Re: Changing colours mathematically
16-01-2020 10:57 AM
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Depending on where you were out by two, may or may not affect the actual colour, for example, if it were say 54 instead of 52 then no huge difference but if it were 72 or 32 then yes these are obvious changes of colour.
So to clarify @Luzern, what exactly is it you are trying to achieve here?
Re: Changing colours mathematically
16-01-2020 11:36 AM
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Assuming you are trying to correct a photo of something, Then the most likely explanations for the error are
a) the white balance of the photo is off due to the lighting conditions when you took the picture. Photo Plus ( Photo Fix tool, White balance filter) wil let you adjust the white balance for the image. I usually use the colour eyedropper on something in the image known to be white, then play with the adjustments until it shows up as white (0,0,0).
b)As I said earlier, it may be that the .jpg you are trying to adjust has dithered the colour to get an accurate impression of the colour. Camera sensors and displays only have three colours (red, green and blue) to get intermediate colours they dither the pixels so that the eye sees the composite of the three. It may be that the specific pixel you picked up with the eyedropper is one of the colours that have been dithered. Expand ( Zoom in) the image until you can see the individual pixels, and use the eye dropper at that resolution.
c) Where did you get the information that the colour you are looking for is Electric Blue. Electric Blue may not be electric blue - see attached. I looked it up on a colour standard website https://rgb.to/keyword/7446/1/electric-blue.
The pantone colour seems to be called Electric Blue lemonade, and doesn't actually appear on that swatch.
Re: Changing colours mathematically
16-01-2020 3:19 PM
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I don't understand these things - but not all colours can be expressed as a RGB value.
The word to search for is "colour gamut".
See https://en.wikipedia.org/wiki/Gamut#Representation_of_gamuts 😎
"In The Beginning Was The Word, And The Word Was Aardvark."
Re: Changing colours mathematically
16-01-2020 4:24 PM
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It's been an interesting exercise. I shall leave it there for the particular photo.
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