Re: Color Management for iPad?
Re: Color Management for iPad?
- Subject: Re: Color Management for iPad?
- From: Tom Lianza <email@hidden>
- Date: Mon, 01 Aug 2011 09:25:16 -0400
- Thread-topic: Color Management for iPad?
Hi to all,
The question of mobile color management has come up often and I would like
to take few moments to discuss some of the issues so people have a better
understanding of the issues. This is an area of discussion within the ICC
and we are trying to sponsor a "Color Management on the Web and mobile
environments" conference in November in San Jose.
1. The mobile network providers don't want to see a lot of images on the
network. They use bandwidth (which you are paying for) and it can have a
real impact on through put in crowded urban networks. Mobile providers,
especially in the US, would rather not have to deal with the issues images
at all.
2.ICC profiles are effectively user-supplied, binary, meta data which is an
absolute negative security issue on a mobile network. The reason that phone
applications are so carefully screened and the development environments are
so tightly bound to the OS is the fundamental security issue. An
application CANNOT BE ALLOWED to bring down a phone, hence they will be
restricted to very carefully controlled application memory space. I
seriously doubt that user supplied profiles will ever be used at the highest
level in a mobile device. At best, it will be application based. An app on
a phone is far more restricted than an application on the desktop. The
browser issue is more complex because it should run seamlessly in both
worlds.
3. For traditional color management to work, there must be a source and a
destination defined BEFORE RENDERING. The question of untagged (source
unknown) has generally been defined to be sRGB. If that assumption is
followed in the system, a very good rendering of sRGB to display can be done
with a relatively simple transformation. The fact is that nearly all mobile
devices do this in the hardware pipeline. The need to accommodate a wide
range of display technologies is well understood and graphics engine
designers have various color correction hardware built into the chip. From
the standpoint of the mobile designer, they already have done "color
management" and the fact that you can't see it or change it is of no
consequence to them. If you render the image to sRGB, leave it untagged,
there will be no major surprises, unless something stupid happens in the
upload process.
4. I cannot understand how a photographer would allow some alien device,
with unknown rendering characteristics, perform color management on the
image. Given that the trend is towards lower gamut, high luminance
displays, it is very likely that the output after late binding color
management will clip, in relative colorimetric mode. If the manufacturer
decides on a perceptual rendering, then the color you see will be very much
determined by the taste of the platform vendor, not you the photographer.
In any instance, the result that the end user sees, will not be the image
the photographer saw.
When it comes to general color management on the Web and mobile devices, be
careful what you wish for...it can get ugly and you would never see it
unless you happened to have the same mobile device as the customer. I am
trying to get developers and users at the same table during the planned
conference. Getting angry users is easy, getting willing developers...not
so easy...
Regards,
Tom
On 8/1/11 3:57 AM, "Jan-Peter Homann" <email@hidden> wrote:
> Hello Stéphane,
> Thanks for your very useful reply. Now it is clear, that the iOS /
> Quartz documentation from Apple is misleading to developers.
> Apple states inside the iOS documentation: "The Quartz 2D API is easy to
> use and provides ... advanced color management"
>
> http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptu
> al/drawingwithquartz2d/Introduction/Introduction.html#//apple_ref/doc/uid/TP30
> 001066
>
>
> If all the advanced colormanagement of Quartz can´t be used in iOS,
> Apple has to change its iOS documentation.
>
> Question to John Gnaegy, Manager of this list:
> - Does Apple know, that the iOS / Quartz documentation is wrong
> concerning color management ?
> - Are there any plans from Apple to provide a correct documentation ?
> - Are there any plans from Apple to provide a ColorSync API for iOS ?
>
> Best regards
> Jan-Peter
>
>
> Am 31.07.11 22:15, schrieb Stéphane Beaudry:
>> Greetings,
>>
>> I have worked as a developer for color management applications for over 6
>> years (Windows& MacOS) but I have spent the last two years and half as a
>> mobile developer (iOS, Android and Blackberry) for other fields of
>> application. When I first started on the iPhone, I tried out of curiosity to
>> see how well color management was supported on it. Of course, it wasn't. At
>> all.
>>
>> As of iOS 4.3, there is still no general color management support, no matter
>> what the Quartz API promises. The whole ColorSync API is also missing from
>> the iOS.
>>
>> Some portfolio viewing applications advise their users to save the images
>> using the sRGB color space since they claim it is the closest match for the
>> iPad's native color space. Of course, this is not satisfactory for a useful
>> preview. Also, it would be very interesting to get additional information
>> from the image such as matching tolerances, switching between rendering
>> intents, etc.
>>
>> There are indeed ways to build an iPad application which performs the tasks
>> of reading profiles and performing the proper conversions for images. The iOS
>> frameworks do provide useful tools to edit even large files efficiently.
>> Communicating between desktop and mobile applications has never been easier
>> and may even get better when iOS 5 gets released. In short, there is a lot
>> developers can already do to create interesting applications related to color
>> management. It is quite challenging because mobile frameworks are still
>> struggling to grow up (just take a look at Bluetooth on the iPad) but it is
>> not impossible.
>>
>>
>> Stéphane Beaudry
>> Lead Developer / Mobile Applications
>> Innobec Technologies Inc.
>>
>>
>> Le 2011-07-30 à 16:52, Jan-Peter Homann a écrit :
>>
>>> Hello to all,
>>> I just subscribed to the colorsync developers list to ask some questions.
>>> It may helps if other people also subscribe and state, that they are
>>> interested for an answer.
>>>
>>> Jan-Peter
>>>
>>> ******
>>> Following questions I have sent
>>> *******
>>>
>>> Hello to all,
>>>
>>> The iOS documentation states, that ICC-profiles should be supported through
>>> Quartz.
>>>
>>> But user tests have shown, that currently no Apple iOS application for iPad
>>> seems to support ICC-profiles.
>>>
>>> Is this a problem of the current Apple applications or are there differences
>>> in Quartz ICC-profile support between iOS and Mac OS X, which are not
>>> mentioned in the official documentation ?
>>>
>>> I´m also interested on:
>>> - does iOS 4 provides a color characterization / profile for the display ?
>>> - If yes, is this an ICC-profile or an internal format because of speed
>>> optimization ?
>>> - if yes, is there any documentation about it ?
>>> - if yes, is this hardcoded, or can a developer change the display color
>>> characterization / profile ?
>>>
>>> Thanks and best regards
>>> Jan-Peter
>>>
>>>
>>>
>>> Am 30.07.11 18:54, schrieb Louis Dery:
>>>> In order to validate that ICC profiles are not used in iOS4 basic apps like
>>>> "Mail" (and "Photos"), just send to yourself an e-mail with picture with
>>>> two different ICC profile embedded
>>>> one with Adobe RGB and a copy of this picture with a different ICC profile
>>>> embedded (assigned) like ProPhoto RGB.
>>>> You will see in Mail (on the iPad) that they look the same! Check this
>>>> e-mail on you Mac with "Mail" app and will see that they are different!
>>>>
>>>>
>>>> Hope this is more clear when I mentioned that color management is not
>>>> implemented in iOS4, like it is on Mac OS X.
>>>>
>>>> Louis Dery
>>>> www.couleur911.com _______________________________________________
>>>> Do not post admin requests to the list. They will be ignored.
>>>> Colorsync-users mailing list (email@hidden)
>>>> Help/Unsubscribe/Update your Subscription:
>>>> ment.de
>>>>
>>>> This email sent to email@hidden
>>>>
>>>
>>> --
>>> ---------- Please note the new adress --------------
>>>
>>> homann colormanagement --------- fon +49 30 611 075 18
>>> Jan-Peter Homann ------------ mobile +49 171 54 70 358
>>> Cotheniusstr. 3 -------- http://www.colormanagement.de
>>> 10407 Berlin -------- mailto:email@hidden
>>>
>>>
>>> _______________________________________________
>>> Do not post admin requests to the list. They will be ignored.
>>> Colorsync-users mailing list (email@hidden)
>>> Help/Unsubscribe/Update your Subscription:
>>> com
>>>
>>> This email sent to email@hidden
>>>
>>
>
The information contained in this e-mail and any accompanying attachments may contain information that is privileged, confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message and any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited. The company accepts no liability for any damage caused by any virus transmitted by this email or any attachments.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden