Re: Re: Color depth - Wikipedia, the free

• To: mathgroup at smc.vnet.net
• Subject: [mg105279] Re: [mg105231] Re: [mg105150] Color depth - Wikipedia, the free
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Wed, 25 Nov 2009 23:02:49 -0500 (EST)
• References: <200911221111.GAA10588@smc.vnet.net>
• Reply-to: drmajorbob at yahoo.com

```That definitely answers the question, I'd say.

And you're right, my apologies... I stopped reading too soon, or stopped
paying attention.

(Sometimes it's "Short Attention-Span Theater", here.)

Bobby

On Wed, 25 Nov 2009 17:42:21 -0600, Patrick Scheibe
<pscheibe at trm.uni-leipzig.de> wrote:

> Hi,
>
> why do you quote just this sentence and not the one where I said that
> it's not clear what exactly this means?
> But to make it clear: on my system
>
> img = With[{n = 16^2},
>     ArrayFlatten[
>      Partition[
>       Table[{x, y, z}, {z, 0, 1, 1/(n - 1)}, {y, 0, 1, 1/(n - 1)}, {x,
>          0, 1, 1/(n - 1)}], Sqrt[n]]]] // Image[#, "Real"] &;
> Export["~/tmp/24bit.bmp", img, "ColorDepth" -> 24]
>
> results in an image which really has 256^3 different colors and *no*, I
> could not see the difference between adjacent pixels since my eyes are
> too bad. But Gimp told me that every pixel is different and
>
> img2 = Import["~/tmp/24bit.bmp"];
> Union@Flatten[img2[[1]], 1] // Dimensions
>
> {16777216, 3}
>
> looks promising too.
> I hope this was what Roger wanted to know.
>
> Cheers
> Patrick
>
>
> On Wed, 2009-11-25 at 16:53 -0600, DrMajorBob wrote:
>> > every pixel has different rgb-values. This means if you put n=16^2 you
>> > would have 256x256x256 colors...
>>
>> No... it means you'd have RGBColor with 256x256x256 distinct parameter
>> triplets. That doesn't prove they're all distinct, implemented COLORS.
>>
>> We could set n=1024^2 just as easily, but is there an implemented color
>> model (in Mathematica) with the required depth?
>>
>> Bobby
>>
>> On Wed, 25 Nov 2009 01:31:41 -0600, Patrick Scheibe
>> <pscheibe at trm.uni-leipzig.de> wrote:
>>
>> > Hi,
>> >
>> > assume the following graphic in Mathematica
>> >
>> > With[{n = 4^2},
>> >   ArrayFlatten[
>> >    Partition[
>> >     Table[{x, y, z}, {z, 0, 1, 1/(n - 1)}, {y, 0, 1, 1/(n - 1)}, {x,
>> >       0, 1, 1/(n - 1)}], Sqrt[n]]]] //
>> >  ArrayPlot[#, ColorFunction -> RGBColor] &
>> >
>> > when you check the values for the colors in this image you'll see that
>> > every pixel has different rgb-values. This means if you put n=16^2 you
>> > would have 256x256x256 colors in the image which is exactly what
>> > "millions of colors" is supposed to be.
>> > Since the table creates rational expressions for the {r,g,b} colors
>> you
>> > could easily (with the restriction that an image of that size would
>> take
>> > too long to render in Mathematica) create more colors by setting
>> higher
>> > values to n.
>> >
>> > But what does this mean? Are there really that many visible colors on
>> > your screen? What happens if you export the image?
>> > This depends many things, e.g. on your os-settings.
>> >
>> > So if you really want to know more, you have to tell more about what
>> you
>> > try to achieve and which things are not working for you.
>> >
>> > Cheers
>> > Patrick
>> >
>> >
>> >
>> >
>> >
>> > On Sun, 2009-11-22 at 06:11 -0500, Roger Bagula wrote:
>> >> http://en.wikipedia.org/wiki/Color_depth
>> >>
>> >> Does anyone know how to access thousand and millions of
>> >> colors in Mathematica?
>> >>
>> >> Respectfully, Roger L. Bagula
>> >> 11759 Waterhill Road, Lakeside,Ca 92040-2905,tel: 619-5610814 :
>> >> alternative email: roger.bagula at gmail.com
>> >>
>> >>
>> >>
>> >
>> >
>>
>>
>

--
DrMajorBob at yahoo.com

```

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