Anti aliasing

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Posted By
Bren
Jan 20, 2005
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425
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7
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I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’ All the selection tools have the option of anti aliasing. As far as I can see anti aliasing blurs the line between different tones. Surely this reduces sharpness. Can anyone please tell me why Photoshop pictures are ‘anti aliased’

Brendon Cottrell

Must-have mockup pack for every graphic designer 🔥🔥🔥

Easy-to-use drag-n-drop Photoshop scene creator with more than 2800 items.

CG
Claim Guy
Jan 20, 2005
"Bren" wrote in message
I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’ All the selection tools have the option of anti aliasing. As far as I can see anti aliasing blurs the line between different tones. Surely this reduces sharpness. Can anyone please tell me why Photoshop pictures are ‘anti aliased’

Brendon Cottrell

Here’s a layman’s explanation that may be enough for you. If not, I’m sure some of the other folks here can get dirtier with it

Deciding to Use Font Smoothing on Web Images
The fur was flying in our Web group the day we decided to make a definitive decision about whether to use anti-alias on our site. Up until that day, it had depended upon the whim of the designer or graphic artist whether the text was aliased or not.

Then I happened upon an article that indicated that that strange box in Photoshop was not just there to fill up space.

I did some more research and found out that our technical writer advised to always leave it unchecked. When I asked her why, she stated that anti-alias messes up printing. Then I spoke to our graphic artist, and she said to always leave it checked. When I asked her why, she stated that otherwise graphics would look awful on the Web. The more people I spoke to, the more opinions I heard. Until we were in the meeting room with our books and stacks of research arguing about who was right.

What is Aliasing?
All computer displays show images in bitmap mode. What this means is that every image is really a bunch of tiny little squares that make up the image. What this essentially means is that computers can’t display really smooth curves.

How does anti-aliasing work?
Anti-aliasing works with the way that our eyes see things. Human eyes do not see in as precise detail as we would like to think. In reality, the mind converts the images into what it "thinks" they are supposed to look like.

With anti-aliasing, the curve is created with squares of color that are shaded darker or lighter depending on how much of the curve would take up that square. For instance, if a portion of a curve takes up 10% of a pixel, that pixel would be shaded with 10% of the color saturation of the curve.

What this amounts to is that anti-aliasing adds shading along the curve to "fool the eye" into thinking it’s seeing a smooth curve rather than a jagged bitmap.

Why should I be "anti" aliasing?
Well, this depends on your point of view. There are as many reasons to alias images and fonts on the Web as there are to anti-alias them.

Anti-aliasing Pros and Cons
Pros

a.. Makes fonts look smoother
b.. Rounded edges look round
c.. Type is easier to read (for some) because it looks more like what printed type looks like
d.. It’s just plain prettier (some would argue)
Cons

a.. Small fonts become too fuzzy to read
b.. Sharp edges may be fuzzy and not precise
c.. You can’t print anti-aliased text as it comes out blurred
d.. Images are generally larger
e.. Type is easier to read (for some) because the blurring is reduced and the fonts are clear
What did we decide?
We decided to use anti-aliasing most of the time. The only time we don’t use it is when we want a specific effect for a graphic (sometimes we might like the jaggies!), or with fonts smaller than 10 to 12 points. We also strive to use browser font treatments rather than images, so that when the pages are printed, the printer can decide.
EG
Eric Gill
Jan 20, 2005
Bren wrote in gui.ntli.net:

I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’

No, you haven’t – unless someone was lying to you. Stuff that you draw on an image and some transferforms has antialiasing applied to it, otherwise it would look pixelated.
S
steggy
Jan 20, 2005
Claim Guy wrote:
"Bren" wrote in message
I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’ All the selection tools have the option of anti aliasing. As far as I can see anti aliasing blurs the line between different tones. Surely this reduces sharpness. Can anyone please tell me why Photoshop pictures are ‘anti aliased’

Brendon Cottrell

Here’s a layman’s explanation that may be enough for you. If not, I’m sure some of the other folks here can get dirtier with it

I would like to complement you with this fine explanation:))

I for one have nothing to add LOL

steg
S
SCRUFF
Jan 20, 2005
"Eric Gill" wrote in message
Bren wrote in gui.ntli.net:

I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’

No, you haven’t – unless someone was lying to you. Stuff that you draw on an image and some transferforms has antialiasing applied to it, otherwise it would look pixelated.
Lying? Or simply misinformed!
EG
Eric Gill
Jan 20, 2005
"Scruff" wrote in news::

"Eric Gill" wrote in message
Bren wrote in gui.ntli.net:

I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’

No, you haven’t – unless someone was lying to you. Stuff that you draw on an image and some transferforms has antialiasing applied to it, otherwise it would look pixelated.
Lying? Or simply misinformed!

Someone who made this claim in print/professionally is either lying about their knowledge of image processing, or for some reason lying about Photoshop.

Take your pick.
C
Corey
Jan 21, 2005
"Eric Gill" wrote in message
"Scruff" wrote in news::

"Eric Gill" wrote in message
Bren wrote in gui.ntli.net:

I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’

No, you haven’t – unless someone was lying to you. Stuff that you draw on an image and some transferforms has antialiasing applied to it, otherwise it would look pixelated.
Lying? Or simply misinformed!

Someone who made this claim in print/professionally is either lying about their knowledge of image processing, or for some reason lying about Photoshop.

Take your pick.

There’s a HUGE difference between making a false statement and lying. A false statement can be made without knowledge that the statement is indeed false and without any intention of deceit. Lying is intentionally deceitful and the person making the statement knows it is false.

Thousands of years ago, people thought the sun revolved around the earth and often stated so as fact. These statements we now know were false, but the people making the claim were not lying. They were, as Scruff correctly states, "simply misinformed."

Remembering this distinction can prevent then inevitable apology.

Peadge 🙂
B
Bren
Jan 21, 2005
Bren wrote:
I’ve read somewhere that all pictures displayed in Photoshop are ‘anti aliased’ All the selection tools have the option of anti aliasing. As far as I can see anti aliasing blurs the line between different tones. Surely this reduces sharpness. Can anyone please tell me why Photoshop pictures are ‘anti aliased’

Brendon Cottrell

Thank you all for your comments. The sentence which gave me this information comes from the ,creativepro.com, web site. a well respected source of information.
However I am mislead, it actually says when talking about sharpening a picture
"Photoshops zoomed-out views (other than 50% and 100%) are heavily antialiased, so they don’t offer a particularly accurate impression of sharpness.
I would be interested to hear your further comments

Brendon Cottrell

Must-have mockup pack for every graphic designer 🔥🔥🔥

Easy-to-use drag-n-drop Photoshop scene creator with more than 2800 items.

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