Ad
Ad
Ad
Pages: « 1 [2]   Bottom of Page
Print
Author Topic: Prepare gallery for web - Colour space  (Read 6309 times)
jule
Sr. Member
****
Offline Offline

Posts: 738


WWW
« Reply #20 on: September 24, 2008, 07:45:53 PM »
ReplyReply

Quote
"June 2008 PC users now have the availability of Safari (from Apple) or Firefox 3, both of which support colour management. Unfortunately Firefox 3 currently needs colour management enabling..."

http://www.northlight-images.co.uk/article...management.html
[a href=\"index.php?act=findpost&pid=224076\"][{POST_SNAPBACK}][/a]

Thanks Alaska for the link, which I had come across before. It is good to see samples of images which have profiles embedded and not embedded, and their resultant display on my monitor. I obviously do not have colour management happening with my browser. I will download Firefox 3 and see what changes occur.

From what I can determine from the link above, there is no visual difference between the images with the Adobe 98 profile embedded and the one without. Similarly, there seems to not be a difference between the image with sRGB embedded and the one without. So the aim to embed a profile is obviously have browsers which can render the colours correctly of the image with the embedded profile. So... with browsers starting to adopt colour management, it is difficult when situations like this result. -
Update, June 21, 2008 : We've received a small but steady stream of reports, primarily from Mac users, that enabling colour management in Firefox 3 causes certain hues in pictures with embedded profiles to display differently than either Photoshop or Safari, and in some cases the difference has been described as dramatic and that Firefox seems to be the one rendering the affected colours incorrectly. We've not seen this problem, either in the release version of Firefox 3 nor in daily use of betas over the past several months, but it's becoming clear that some users' machines are affected and that it's negating the benefit of turning on colour management in the new Firefox.

.....so if embedding the profile is causing colour shifts with some users in this new development in colour management of the internet, the same question arises - should a profile be embeded? why or why not?

Julie
Logged

jbrembat
Full Member
***
Offline Offline

Posts: 177


« Reply #21 on: September 25, 2008, 02:54:02 AM »
ReplyReply

Quote
....management of the internet, the same question arises - should a profile be embeded? why or why not?.so if embedding the profile is causing colour shifts with some users in this new development in colour
Julie,
 I don't know if there is a bug on Firefox color management.
But if the bug exists, I suppose it will be fixed.

Should a profile be embedded? Sure. It is beneficial for users which browser is color-managed.

Don't forget to upload sRGB images, as most of the monitors are sRGB-like.

Jacopo
Logged
jule
Sr. Member
****
Offline Offline

Posts: 738


WWW
« Reply #22 on: September 28, 2008, 04:39:04 PM »
ReplyReply

Quote
Julie,
 I don't know if there is a bug on Firefox color management.
But if the bug exists, I suppose it will be fixed.

Should a profile be embedded? Sure. It is beneficial for users which browser is color-managed.

Don't forget to upload sRGB images, as most of the monitors are sRGB-like.

Jacopo
[a href=\"index.php?act=findpost&pid=224229\"][{POST_SNAPBACK}][/a]

Thanks Jacopo and all those who contributed. Seems as if this is a time where colour management on the web is being addressed but still has a fair way to go.

Julie
Logged

Chris_Brown
Sr. Member
****
Offline Offline

Posts: 787



WWW
« Reply #23 on: September 28, 2008, 05:13:52 PM »
ReplyReply

Quote
I would appreciate some thoughts on the most appropriate way to prepare files for a web gallery
Prepare the files for the worst viewing conditions within your market. Embed the sRGB_IEC61966-2-1_withBPC.icc profile. Set files between 75-85 dpi and sharpen at 100% of viewing conditions. Be aware that Flash does not support ICC profiles (i.e., the Flash engine strips the profile from the image), and that certain php scripts do not support embedded ICC profiles. Test, test, test.
Logged

~ CB
jbrembat
Full Member
***
Offline Offline

Posts: 177


« Reply #24 on: September 29, 2008, 08:54:29 AM »
ReplyReply

Quote
Prepare the files for the worst viewing conditions within your market. Embed the sRGB_IEC61966-2-1_withBPC.icc profile. Set files between 75-85 dpi and sharpen at 100% of viewing conditions. Be aware that Flash does not support ICC profiles (i.e., the Flash engine strips the profile from the image), and that certain php scripts do not support embedded ICC profiles. Test, test, test.
[a href=\"index.php?act=findpost&pid=225317\"][{POST_SNAPBACK}][/a]

Julie,
 ignore the dpi (ppi is the correct term) advice. The PPI value embedded into the image file does'nt make any difference.
The image dimension (in pixels) must be compatible to screen resolution.


Jacopo
Logged
digitaldog
Sr. Member
****
Offline Offline

Posts: 9004



WWW
« Reply #25 on: September 29, 2008, 08:58:28 AM »
ReplyReply

Quote
I'm still confused and would like to understand.  Digitaldog, I would love a brief outline of why you would, or would not, embed the sRGB profile for web display?

Only two browsers will "see" the embedded profiles.
If you're concerned about speed for users and storage, the addition of the 4K used by the profile may be an issue. If you don't care that each image is that much larger (you're not uploading thousands of images), go ahead and embed, but it will make little difference to the vast majority of users because their browsers simply don't know they exist.

Of course, you have to currently convert to sRGB! There's no debate about that.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
digitaldog
Sr. Member
****
Offline Offline

Posts: 9004



WWW
« Reply #26 on: September 29, 2008, 08:59:26 AM »
ReplyReply

Quote
Be aware that Flash does not support ICC profiles (i.e., the Flash engine strips the profile from the image), and that certain php scripts do not support embedded ICC profiles. Test, test, test.
[a href=\"index.php?act=findpost&pid=225317\"][{POST_SNAPBACK}][/a]

Flash 10 does support this now.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Chris_Brown
Sr. Member
****
Offline Offline

Posts: 787



WWW
« Reply #27 on: September 29, 2008, 10:07:01 AM »
ReplyReply

Quote
The image dimension (in pixels) must be compatible to screen resolution.
And exactly what is that?
Logged

~ CB
jbrembat
Full Member
***
Offline Offline

Posts: 177


« Reply #28 on: September 29, 2008, 10:38:33 AM »
ReplyReply

Quote
And exactly what is that?
[a href=\"index.php?act=findpost&pid=225518\"][{POST_SNAPBACK}][/a]

For example 800x600 pixel. Nothing to do with PPI.

Jacopo
Logged
Chris_Brown
Sr. Member
****
Offline Offline

Posts: 787



WWW
« Reply #29 on: September 29, 2008, 03:59:46 PM »
ReplyReply

Quote
For example 800x600 pixel. Nothing to do with PPI.
Yes, I agree. DPI is incorrect terminology when resizing an image in Photoshop -- PPI is correct. However, what I'm referring to is the pixel pitch (also known as dot pitch) of monitors. Back in the day, a pixel pitch of .3mm to .4mm was the norm. Today, monitors can have a much tighter pixel pitch. This resolution directly affects the image size. An image spec'd at 75 ppi will appear much smaller on a 1920×1200 monitor with a .27 ppi pitch, which corresponds to a native resolution of 94 ppi (if an image is to be best viewed that type of monitor, it should be spec'd at 94 ppi).

You said "The image dimension (in pixels) must be compatible to screen resolution". I'm saying there is no definitive global screen resolution, so an estimation must be made about the dot pitch of monitors your images will be viewed on.
Logged

~ CB
jbrembat
Full Member
***
Offline Offline

Posts: 177


« Reply #30 on: September 30, 2008, 02:53:03 AM »
ReplyReply

Quote
Yes, I agree. DPI is incorrect terminology when resizing an image in Photoshop -- PPI is correct. However, what I'm referring to is the pixel pitch (also known as dot pitch) of monitors. Back in the day, a pixel pitch of .3mm to .4mm was the norm. Today, monitors can have a much tighter pixel pitch. This resolution directly affects the image size. An image spec'd at 75 ppi will appear much smaller on a 1920×1200 monitor with a .27 ppi pitch, which corresponds to a native resolution of 94 ppi (if an image is to be best viewed that type of monitor, it should be spec'd at 94 ppi).

You said "The image dimension (in pixels) must be compatible to screen resolution". I'm saying there is no definitive global screen resolution, so an estimation must be made about the dot pitch of monitors your images will be viewed on.
[a href=\"index.php?act=findpost&pid=225629\"][{POST_SNAPBACK}][/a]
The dot pitch value fix the size of a rendered pixel. I agree.
But this value is related to DPI value, not PPI value.

You cannot modify it changing the PPI value embedded in the image file.
If you are in doubt do the following simple test:
  fix the PPI value to 1 and save the image =>IMG1
  fix the PPI value to 1000 and save the image => IMG2
Do not resample, otherwise you are changing the image width and height.
The pixel-width(height) of IMG1 are equal to the pixel-width(height) of IMG2.

Now open IMG1 and IMG2 and check for difference.

For web publishing, it's more simple to think about screen resolution.
If you want to get audience from about all the surfers, you must remember that 800x600 is the resolution of the old  15' CRT.

Jacopo
Logged
Pages: « 1 [2]   Top of Page
Print
Jump to:  

Ad
Ad
Ad