why do my images pixellate in Mac?

D
Posted By
dbl4ck3r
Sep 23, 2004
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360
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I’m just re-learning PS on a Mac, and I’ve noticed something rather strange with images I created on a PC (in TIFF). When I go to ‘actual pixels’, the image is really coarse: the smallest details are made up of blocks of pixels, not single pixels.

The image looks as though it’s been zoomed *way over* 100%, which it hasn’t.

Just why am I losing so much image detail this way? Are TIFFS saved on a PC incompatible with Macs?
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tacitr
Sep 23, 2004
Just why am I losing so much image detail this way? Are TIFFS saved on a PC incompatible with Macs?

No. A TIFF is a TIFF is a TIFF; it’s identical on Macs, PCs, Suns, Amigas, mainframes, you name it.

What happens when you look at actual pixels on a PC? It should be 100% pixel-for-pixel identical to the same image viewed at "actual pixels" on a Mac.

If you have an image that’s not the same on both, email it to me off-list; I’d love to take a look at it.

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Tom Nelson
Sep 23, 2004
I’ll bet your Mac has a low bit depth set. In OS X, that’s System Preferences>Displays>Colors>Millions. In OS 9 or less, open the Color (or is it Displays?) control panel.
Tom Nelson
Tom Nelson Photography

In article , dave
blacker wrote:

I’m just re-learning PS on a Mac, and I’ve noticed something rather strange with images I created on a PC (in TIFF). When I go to ‘actual pixels’, the image is really coarse: the smallest details are made up of blocks of pixels, not single pixels.

The image looks as though it’s been zoomed *way over* 100%, which it hasn’t.

Just why am I losing so much image detail this way? Are TIFFS saved on a PC incompatible with Macs?
O
Odysseus
Sep 23, 2004
In article ,
(Tacit) wrote:

Just why am I losing so much image detail this way? Are TIFFS saved on a PC incompatible with Macs?

No. A TIFF is a TIFF is a TIFF; it’s identical on Macs, PCs, Suns, Amigas, mainframes, you name it.

Yes and no: while a single specification covers all the standard options, there are some characteristics typical of certain platforms. For example the sequential arrangement of samples differs between Mac and DOS/Windows versions (I don’t remember exactly how, but it’s something like top-to-bottom-by-rows _vs_ left-to-right-by columns) — although most professional graphics applications, Photoshop certainly included, can recognize and deal appropriately with either platform’s ‘idiom’.

What happens when you look at actual pixels on a PC? It should be 100% pixel-for-pixel identical to the same image viewed at "actual pixels" on a Mac.

If you have an image that’s not the same on both, email it to me off-list; I’d
love to take a look at it.

Ditto.

—
Odysseus
G
Gadgets
Sep 24, 2004
Win default screen res 96DPI (can be set up to 120DPI) Mac screen res 72DPI

Cheers, Jason (remove … to reply)
Video & Gaming: http://gadgetaus.com
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nomail
Sep 24, 2004
"Gadgets" wrote:

Win default screen res 96DPI (can be set up to 120DPI) Mac screen res 72DPI

That was years ago. Today a monitor can be set to different resolutions, so there is no default screen resolution anymore. There is no reason why the image should be pixelated, unless he did something wrong.

—
Johan W. Elzenga johan<<at>>johanfoto.nl Editor / Photographer http://www.johanfoto.nl/
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tacitr
Sep 24, 2004
Yes and no: while a single specification covers all the standard options, there are some characteristics typical of certain platforms. For example the sequential arrangement of samples differs between Mac and DOS/Windows versions…

Actually, that’s not quite correct. The difference between a PC TIFF and a Mac TIFF (actually, it should be "PC" and "anything that is not PC") is the byte order.

Intel processors have a strange quirk that’s a consequence of design decisions Intel made in the old 8080, which still haunt even Pentium processors today: Every pair of digits in any number is swapped.

Say you have the number 1000. To an Intel processsor, this number is represented as "0010" rather than "1000." The number "1234" is represented in
an Intel processor as "3412." The number "1492" is "9214," and so on.

A "PC" TIFF swaps each pair of numbers, so that an Intel processor doesn’t have to swap them back–they’re already represented in what many Unix programmers call "goddamn stupid Intel byte-order."[1]

The TIFF records the byte order in the header; any program on any platform that reads TIFF files can figure out how to represent the numbers correctly.

[1] I kid you not. there’s at least one C compiler I’ve worked with that has a compiler directive to use little-endian byte order; the compiler directive is

# use goddamn stupid intel byte-order

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T
tacitr
Sep 24, 2004
Win default screen res 96DPI (can be set up to 120DPI) Mac screen res 72DPI

That has nothing to do with the original poster’s question, as the TIFF has the resolution saved within its header. And Macs haven’t used 72 pixel per inch screens since about 1994 or so.

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Odysseus
Sep 24, 2004
In article ,
(Tacit) wrote:

Actually, that’s not quite correct. The difference between a PC TIFF and a Mac
TIFF (actually, it should be "PC" and "anything that is not PC") is the byte order.
Ah, thanks for that: so the difference is in the ‘internal’ arrangement of the sample data’s binary representation rather than in the large-scale arrangement of the samples.

[snip]
[1] I kid you not. there’s at least one C compiler I’ve worked with that has a
compiler directive to use little-endian byte order; the compiler directive is
# use goddamn stupid intel byte-order

[vbg] Thanks again!

—
Odysseus

MacBook Pro 16” Mockups 🔥

– in 4 materials (clay versions included)

– 12 scenes

– 48 MacBook Pro 16″ mockups

– 6000 x 4500 px

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