Black Point Compensation, more detail on what's happening?

Photoshop help doesn't explain much about black point compensation. Can someone provide a complete explanation? I am particularly interested in knowing if the black point is being chosen from the image's source and destination ICC profiles, from the image data itself, or a combination of both. Once the black point(s) are determined, what adjustments are done?
Thanks,
-Chris.

A fair bit has been published online on the subject...
Andrew Rodney did a decent job with it... http://thedigitaldog.com/files/Black_Point_Compensation.pdf
-Noel

Similar Messages

Adobe CMM Black Point Compensation

Hello list members,
I have been trying out the Adobe CMM in combination with Adobe Photoshop.
By testing the Black Point Compensation (BPC) preferences, I get strange
results on my PowerMac. This is not happening on an IntelMac for me.
The discussion started on the ColorSync users group and is still going on there,
so maybe others might report there too.
This is my testing basis (All done with ISOcoated to ISOuncoated, relative colorimetric):
(Abbr. Adobe Photoshop Convert to Profile BPC Setting: PS)
(Abbr. Adobe CMM preferences BPC setting: CMM)
PS CMM Expected Happening
On On BPC taking place OK
On Off BPC taking place NOT Ok, no BPC happening
Off On BPC taking place OK
Off Off NO BPC OK
Any feedbacks are welcomed.
Regards
Rolf Gierling

In rare cases using Black Point Compensation can cause unacceptable results and the effect is usually washed out detail in the very dark regions of the final image. In our experience this problem usually rears its ugly head with some RGB output profiles.
Adobe recommends, and we agree, that in almost all cases, Black Point Compensation should be on when dealing with CMYK files (doing
RGB to CMYK conversions or CMYK to CMYK conversions). In most cases, doing RGB to RGB conversions without Black Point Compensation will produce desirable prints. However, depending on the profile, doing a conversion from RGB to RGB with Black Point Compensation can produce
poor output with washed out blacks.
It appears that this problem with some RGB profiles is dependent
on the software that is used to generate the profile. Apparently there is a Black Tag feature in ICC profiles that in some cases can be used or unused depending on the software that actually creates the profile. For this reason, there is no hard and fast rule that says we should or should not use Black Point Compensation with RGB output. Our recommendation is to turn off Black Point Compensation with RGB output profiles or if possible, try a test with Black Point Compensation
on and off.
There is one other case where you may want to turn off Black Point Compensation. When you want to soft proof output for a printer that has a low dynamic range like newspaper, where the blacks are
usually not very dense. By turning off the Black Point Compensation, the soft proof is more accurate in predicating the effect of this low dynamic range. Black Point Compensation should be turned off
in the CMYK Set-Up. You can view full information for this problem source www.digitaldog.net/files/Black_Point_Compensation.pdf
Sincerely, Shair

Black point compensation

I have a problem with Black Point Compensation in the print dialog when printing my book pages. It almost seems that the on/off toggle is reversed. I usually have BPC on when printing in Photoshop and I can preview its effect there. I use Relative Colorimetric rendering and having BPC on is invariably better. When previewing the effect in Aperture's print dialog window on the other hand I seem to pretty much get the reverse of what I see in the Photoshop preview. In other words now having BPC turned off not only looks better in the preview, it's also better in the actual print. Has anyone encountered this? Is this a possible bug?

Hi Markus,
Not quite - what the article shows is that BPC is generally a good choice if you are moving from a color space or range of colors in your image (Adobe RGB, for example) that are greater than those in the destination space (nearly any print device) because it keeps the tonal range of the shadows in the image correctly related to each other by mapping the blackest black in your image to the blackest black possible on your output device then shifts the other blacks relatively. As John Nate says:
"the maximum black in Adobe RGB will be remapped to the slightly less dense black of the inkjet printer and all of the other tones will scale accordingly"
However, if you then have a situation where you have an image that has a very restricted black tonal range - an image that has already been prepared for newsprint, for example - and convert it to another space - Adobe RGB, for example - then instead of mapping the image accurately as it would appear in newsprint, BPC over-compensates and shifts the washed-out blacks of the 'correct' newsprint image to the deep blacks possible in Adobe RGB. So, if you are trying to get an accurate on-screen or inkjet proof from the newsprint-ready image, BPC will mess things up.
In short, most of the time when you are moving from sRGB or Adobe RGB etc. to inkjet or print, you can fairly safely leave it on. When you are dealing with images already converted to CMYK, and you want to maintain their appearance as it will be seen on print, it is best to leave it off.
Powerbook, Mac Mini (Intel) Mac OS X (10.4.8)
Powerbook, Mac Mini (Intel) Mac OS X (10.4.8)

Black Point Compensation for JPEG export?

Hiya,
I'd like to print photos via the web, and therefore want to export the photos as JPEGs. I just checked the options in the export preset panel, and realised that one can select "Black Point Compensation" as an option for the export.
Does anyone have any experience with this setting? Should one use it, if one doesn't know the printer in use?
Thanks in advance for any feedback.
Regards,
Stephan

Stephan,
I'd like to print photos via the web, and therefore
want to export the photos as JPEGs. I just checked
the options in the export preset panel, and realised
that one can select "Black Point Compensation" as an
option for the export.
Does anyone have any experience with this setting?
It's a fairly reliable fix if your test prints come back with murky shadows.
Should one use it, if one doesn't know the printer in
use?
I don't know of a good way to optimize files for unknown printers. I'd recommend getting a profile for the printer/paper combo used by your lab and soft-proofing on your Mac. Have you calibrated your screen, etc.?
The soft proof will get you in the ballpark. Definitely order small (8x10 or so) test print before laying out long green for a poster-sized one.
Cheers,
Andreas

Black point compensation for onscreen proofing

Hi there,
In Aperture, is there any way to turn Black point compensation on for onscreen proofing (i.e. not using the export procedure, where this actually is available)? This option is available in Photoshop, for example.

Stephan,
I'd like to print photos via the web, and therefore
want to export the photos as JPEGs. I just checked
the options in the export preset panel, and realised
that one can select "Black Point Compensation" as an
option for the export.
Does anyone have any experience with this setting?
It's a fairly reliable fix if your test prints come back with murky shadows.
Should one use it, if one doesn't know the printer in
use?
I don't know of a good way to optimize files for unknown printers. I'd recommend getting a profile for the printer/paper combo used by your lab and soft-proofing on your Mac. Have you calibrated your screen, etc.?
The soft proof will get you in the ballpark. Definitely order small (8x10 or so) test print before laying out long green for a poster-sized one.
Cheers,
Andreas

My screen goes black then macbook restarts...what's happening?

my screen goes black then macbook restarts...what's happening? This has been happening often (3-4 times per day). Not sure what kind of problem I am dealing with. ideas?

I have had Similar issues in my case it only seems to happen when the laptop is plugged into power. also if you shine a light through the apple logo on the front of the case you can see the LCD is actually running as is the OS it would appear the backlight is off. In my case I can resume operation by taping the F1 or F2 keys. All be it an annoying finx it is at least a simple one

More Details about Multithreading Mode in User Management

Good morning,
we are working with Portal 7.0 on SP 14 and there is an option to activate the multithreading mode
in the User Management part of the support desk. Since this option seems to significant speed up our
login time i´am interested in more details about what is happening here. But i was unable to locate
any documentation / forum entries / blogs about it. Another point is the question if it is possible
to persist that option. After every Node / Serverrestart multithreading gets deactivated again.
Any Ideas / Links / Helps would be appreciated and points will be rewarded.
Thank you,
Marco

Hi
Here is a useful HDD password summary:
http://aps2.toshiba-tro.de/kb0/TSB6B01MC000CR01.htm
_HDD User Password and HDD Master Password:_
There are two levels of the HDD Password, the HDD User Password and the HDD master Password. If both levels of HDD Password have been registered, you can access the HDD by entering either of them. TOSHIBA Password Utility (TPU) only supports the HDD User Password. If you want to register both, open BIOS SETUP. If the HDD User Password has been registered, the HDD Master Password can not be registered
Hope this helps a little bit

Adjusting black point

I prefer to adjust the exposure sliders with the keyboard's arrow buttons. But adjusting the Black Point this way is hopeless, because the steps are way too small to give any noticeable change. The steps are divided up as 0.05, 0.10, 0.15 and so on. But I can't really see any difference before I've adjusted a whole number, from 3.0 to 4.0 and 5.0 etc.
I think the first version of Aperture had these bigger steps, and then they changed it, maybe to have the same steps as the other exposure sliders. But I think a 1.00 step on Black Point corresponds more to a 0.05 step on the other sliders. So changing it back would be much more meaningful. What do you think?

"{Shift}+arrow" will get you tenths instead of twentieths. That's all I got. :-)

Error while accessing SharePoint 2013 news feed REST api - "The server encountered an error processing the request. See server logs for more details."

Hi Experts,
I am facing an issue while accessing SharePoint 2013 news feed REST api URL <SiteCollectionURL>/_api/social.feed/my/news from browser giving error "The server encountered an
error processing the request. See server logs for more details."
This is happening after posting the image to news feed without entering any text or description with that. If i post an image with some text or description, then i can able to get the feeds. Or else if i delete the image post then also i can able to get
the feeds.
I can able to see below logs in log files.
Exception occured in scope Microsoft.Office.Server.Social.SPSocialRestFeed._SerializeToOData. Exception=System.MissingMethodException: No parameterless constructor defined for this object. at System.RuntimeTypeHandle.CreateInstance(RuntimeType
type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache,
StackCrawlMark& stackMark) at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) at System.Activator.CreateInstance(Type type, Boolean nonPublic)
at System.Activator.CreateInstance(Type type) at Microsoft.SharePoint.C...
...lient.ValueTypeConverter.<GetODataProperties>d__2.MoveNext() at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteProperties(IEdmStructuredType owningType, IEnumerable`1 cachedProperties, Boolean isWritingCollection,
Action beforePropertiesAction, Action afterPropertiesAction, DuplicatePropertyNamesChecker duplicatePropertyNamesChecker, EpmValueCache epmValueCache, EpmSourcePathSegment epmSourcePathSegment, ProjectedPropertiesAnnotation projectedProperties)
at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteComplexValue(ODataComplexValue complexValue, IEdmTypeReference metadataTypeReference, Boolean isOpenPropertyType, Boolean isWritingCollection, Action beforeValueAction, Action afterValueAction,
DuplicatePropertyNamesChecker duplicatePropertyNa...
...mesChecker, CollectionWithoutExpectedTypeValidator collectionValidator, EpmValueCache epmValueCache, EpmSourcePathSegment epmSourcePathSegment, ProjectedPropertiesAnnotation projectedProperties) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteProperty(ODataProperty
property, IEdmStructuredType owningType, Boolean isTopLevel, Boolean isWritingCollection, Action beforePropertyAction, EpmValueCache epmValueCache, EpmSourcePathSegment epmParentSourcePathSegment, DuplicatePropertyNamesChecker duplicatePropertyNamesChecker,
ProjectedPropertiesAnnotation projectedProperties) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteProperties(IEdmStructuredType owningType, IEnumerable`1 cachedProperties, Boolean isWritingCollection, Action beforePropertie...
...sAction, Action afterPropertiesAction, DuplicatePropertyNamesChecker duplicatePropertyNamesChecker, EpmValueCache epmValueCache, EpmSourcePathSegment epmSourcePathSegment, ProjectedPropertiesAnnotation projectedProperties) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteComplexValue(ODataComplexValue
complexValue, IEdmTypeReference metadataTypeReference, Boolean isOpenPropertyType, Boolean isWritingCollection, Action beforeValueAction, Action afterValueAction, DuplicatePropertyNamesChecker duplicatePropertyNamesChecker, CollectionWithoutExpectedTypeValidator
collectionValidator, EpmValueCache epmValueCache, EpmSourcePathSegment epmSourcePathSegment, ProjectedPropertiesAnnotation projectedProperties) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSeriali...
...zer.WriteCollectionValue(ODataCollectionValue collectionValue, IEdmTypeReference propertyTypeReference, Boolean isOpenPropertyType, Boolean isWritingCollection) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteProperty(ODataProperty
property, IEdmStructuredType owningType, Boolean isTopLevel, Boolean isWritingCollection, Action beforePropertyAction, EpmValueCache epmValueCache, EpmSourcePathSegment epmParentSourcePathSegment, DuplicatePropertyNamesChecker duplicatePropertyNamesChecker,
ProjectedPropertiesAnnotation projectedProperties) at Microsoft.Data.OData.Atom.ODataAtomPropertyAndValueSerializer.WriteProperties(IEdmStructuredType owningType, IEnumerable`1 cachedProperties, Boolean isWritingCollection, Action beforePropertiesAction,
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Can anyone please help me out.
Thanks!
dinesh

O365,
Is this still an issue?
Thanks!
Ed Price, Azure & Power BI Customer Program Manager (Blog,
Small Basic,
Wiki Ninjas,
Wiki)
Answer an interesting question?
Create a wiki article about it!

My friend in vietnam use my account itunes. He wants to buy credits in app wephone,but he can't, What's happening?

My friend in vietnam use my account itunes. He wants to buy credits in app wephone,he can't buy it, but i can .My account itunes have 100$ more ( gift card), What's happening?

I suspect he needs to contact iTunes support

Am trying to download a plug-in, but am unable to download ANY plugins. I keep getting this: Unexpected installation error Review the Error Console log for more details. -203 What can I do to solve this issue?

I am not able to download ANY plug-ins. All attempts result in the following:
Firefox could not install the file at
https://addons.mozilla.org/en-US/firefox/downloads/latest/10137/addon-10137-latest.xpi?src=addondetail
because: Unexpected installation error
Review the Error Console log for more details.
-203

Hi slysailr ,
Please take a look at this article [[Unexpected installation error -203 when installing add-ons ]], it should help you out with your issue.
Regards,
Ziggy

Should BT be able to provide more detail about usa...

Ok, so I've jut done a bit of searching and found what would be a solution to my problem in the "ideas" section... so commented there also, but so I may get a community opinion, what are your thoughts on the subject of BT providing more detailed usage statistics outside of the BroadBand usage monitor in My-BT? (i.e over the phone / by request on mail / even as an attachment on email notification of additional charges???)
So my story that's prompted this...
I have an option 1 10GB limited service and often get close to it - my average usage is actually 10.1Gb according to the usage monitor as I've had a couple of £5 additional use charges now in the past 6 months... However, today I've received a message saying I'd again exceeded the limit for Feb by using 16Gb... this is the most I've been over (plus £10 charge now) and to make matters worse in Feb, BT managed to disrupt my service (completely disconnected & long story!) for nearly 6 days and therefore I would like to "question" the exceeded usage for the first time - I'd raised a dispute today following the complaint process, and promptly received a returned call...
What I wanted was a breakdown of the usage over Feb PER DAY as I'm pretty sure our surfing habits have not changed, yet I'm well above my average usage even considering I had no internet for 20% of the month!!
I'd also like to have seen in the report that there was no increase of data consumed over the "6 day outage period" - as it would have confirmed to me there was nothing strange going on.
FYI if its relevant to usage totals; to resolve my problem, a BT Openreach engineer was required to visit the exchange to re-patch the broadband service in to my residential line... after some other engineer pulled it out! So there is a risk (in my opinion) that the usage for Feb could be misleading if taken over 2 different connections.
For instance, I know my line is syncing faster than previously & the engineer confirmed I'd been re-connected to different infrastructure in the exchange. (e.g from upto 8MB to the upto 20Mb service???)
When I politely asked for the usage detail on the phone today, I had a point blank refusal! I know the customer version of the usage monitor doesnt provide this level of detail, but really BT, are you telling me you do not have (or could create a report) on my usage by day?
This leaves me with a problem because (again in my opinion) BT are able to abuse the "usage" total and top up their revenue as & when they see fit!!! As a customer, I now feel powerless to challenge it!
My only option is to upgrade to a higher service, when out of the principle of handing over more money, I'm not happy to do at the moment - again BT could easily abuse the supplier position to "push" customers into more expensive service!!!
Back to the phone call today, after explaining my problem & concerns, I got nowhere but the BT agent agreed with everything I said (thanks??? ) and basically said she agreed it was a poor service! lol
Is this a new tactic to agree with everything the customer says but then keep repeating the fact they cant help???
So to wrap this up, I have lost trust in BT and the usage "statistics" and would love for them to try and improve this situation, even make some effort to try to rebuild my lost trust!
I'm almost annoyed enough by this if there is a general consensus/concern to take it further to a watchdog type body, the analogy is putting fuel in the motor without any reading/display at the pump... i.e would you really trust the system is regulated and not open to abuse?? And if you ask for evidence and they wont provide any??? Come on BT, time to improve your customer service!!!
Thanks for reading, please let me know if you have similar experiences

Ok, so this is a list of your addons that will work:
Ad-Block Plus: This will work. You'll have to update to version 2.2.2 after you install Firefox 18, but it will work fine.
Autoformer: This will work fine
iMacros for Firefox: This will also work after an update to 7.6.0.2
Personas: You don't really need this anymore, Firefox has the ability to load Personas built in now. you can remove that add-ons. If you want the addon you can continue to use it.
Tabkit: This was abandoned by it's developer, but you can uninstall it and use https://addons.mozilla.org/en-US/firefox/addon/tabkit-2nd-edition, which is the same thing, just compatible with modern versions of Firefox
Tineye: This will also work after an update to 1.1
All the other extensions you have are disabled.
So, good news, it looks you only need to uninstall tabkit and install tabkit 2, and then update the other add-ons after you install Firefox 18.0.2.
And of course update your plugins ;)

White and black point vs ??

I never know which forum to post these things, so I'll start with the photographers.
 
 These three shots are as follows: (1) the camera raw version, (2) where I moved the sliders from the ends to approximately the beginning/end of the major portion of the histogram, and (3) using the threshold control to find the white and black points in the main part of the picture.
 
 Then, in the two adjusted versions, I lightened the image with the curves control.
 
 In both these cases, I used the grey dropper to touch the same spot on one of the rocks, to get the apparent neutral point.
 
 It seems to me that the threshold method to find the white and black points is preferred, based on the overall color and appearance of the finished adjustment.
 
 But, I've found on some images where the histogram has missing black and missing white, if I adjust the sliders to these two ends, I get pretty much the same outcome, as far as the contrast, color, and grey point.
 
 Could I have some advice on the preferred method to use in handling my image adjustments? Doing it the threshold method takes more time, and sometimes it's difficult to find the white and black points, or even the grey point.
 
 Thanks.
 
 Al
 
 
<a href="http://www.pixentral.com/show.php?picture=1SlEeG9kfwzD34gVOEcCbg7Ktp83p3" /></a>
<img alt="Picture hosted by Pixentral" src="http://www.pixentral.com/hosted/1SlEeG9kfwzD34gVOEcCbg7Ktp83p3_thumb.jpg" border="0" />
 
 
<a href="http://www.pixentral.com/show.php?picture=1tIEs4eAyKz4sxamyVaYRlKjTIIfKj" /></a>
<img alt="Picture hosted by Pixentral" src="http://www.pixentral.com/hosted/1tIEs4eAyKz4sxamyVaYRlKjTIIfKj_thumb.jpg" border="0" />
 
 
<a href="http://www.pixentral.com/show.php?picture=17K3ewFXsGo4K2uH5TGfO06CdVayyn1" /></a>
<img alt="Picture hosted by Pixentral" src="http://www.pixentral.com/hosted/17K3ewFXsGo4K2uH5TGfO06CdVayyn1_thumb.jpg" border="0" />

Yes the image was purposely underexposed. What I was trying to accomplish was to speed up the shutter speed to remove the slight blurring and compensate by pulling data from the shadows. Even though the lens has an image stabilizer the amount of light wasn't enough for a proper sharp shot.
this image is before touch up
These two images are F/5.6, 1/20, ISO 800
After touch up
Better lit scene but shows slight motion blur
This last image is F/5.6, 1/4, ISO 800
I believe that I will have to wait next year and hope I have a faster lens by then. I just don't think the 28mm-135mm f/3.5-5.6 lens is fast enough. I was trying this without a tripod to get in tighter.
Also I was taking these shots without the flash to get the drama of the tree lights.
What I would have prefer is a shutter speed of 1/125 or better as it helps with my hands shaking I believe the slowest should be 1/60
And the lower the ISO the better for noise.
These preferences are what I am used to with my Canon G3 that does not have IS.
I am getting so off track here, lol. But anyways, here are the pictures.

Need more detail description on BIOS voltage

I am using DKA790GX Platinum with AMD X4 940, and I did some Overclocking and now I need more detail on those BIOS Voltage setting:
CPU VDD Voltage?
CPU-NB VDD?
CPU Voltage?
CPU-NB Voltage?
DRAM Voltage?
NB Voltage?
HT Link Voltage?
MCT Voltage?
Also,
What is the difference between CPU Ratio and CPU-NB Ratio?
LaraCroft
DKA790GX PlatinumMS-7550/AMD X4 940 Black Edition/AMI A7550AMS v1.6/3.3Ghz(200x16.5)/CPU Voltage 1.4V/2xCorsairCM2X2048-8500C5D 2048MB 1066MHZ(5-5-5-15)/ZALMAN ZM850-HP/NVIDIA GeForce GTX 280/ST31000528AS(1000 GB)/XP Professional 5.01.2600 Service Pack 3

I'm not familiar with what MCP or MCT voltage is, but I think it's an nvidea thing.
here's a few tips that I've found on oc'ing the 790gx platinum:
Disable Cool & Quiet & C1E.
Disable Spread Spectrum.
Enable HPET. (High Precision Event Timer)
Don't enable the OC option for the onboard graphics. (Should'nt be a problem for your system, since your have an Nvidea GFX card)
I seem to get better results with ACC Disabled, but others have reported some benefit from it set to auto or in the + range.
You may find that bumping up the CPU-NB voltage a little bit may help, but it's dependant on cpu voltage too.
Keep your NB and HT speeds close to stock by reducing their multipliers as needed, OC'ing them won't give you any better performance and it can cause a lot of uneeded problems.
As you start to OC your system, only increase voltages as you neeed to, otherwise leave them on auto or at their recommended settings.
Be sure you start with a completely stable system, Memtest & Prime 95 are your friends (see stickies)! and check your system stability as you go.
Watch your system temperatures, and know the recommended temperature limits for your components. (processor, northbridge, gfx card, etc.
Good luck and have fun!

Videos on iPhoto no longer play. All was fine as I was organizing photos, but suddenly no more videos would play. What has happened?

Videos on iPhoto no longer play. All was fine as I was organizing photos, but suddenly no more videos would play. What has happened?

Something went wrong. Now for a useful answer...
Before anyone can help, they need information to work with. Basic stuff:
- What version of iPhoto.
- What version of the Operating System.
- Details. What were you doing when the problem arose?
- Did it ever work properly?
- Are there error messages?
- What steps have you tried already to solve the issue.
Anything else you can think of that might allow someone else to understand your issue.
With this kind of information somebody can develop a starting point for troubleshooting the issue.
Posts that consist of "iPhoto doesn't work. Help" or "iPhoto won't print" or "Suddenly I have no photos!!!!!!!!!!" mean that any helper is simply guessing. With information, s/he may be able to get your issue resolved sooner.

Black Point Compensation, more detail on what's happening?

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