A white point question ...

Most of the chromaticity diagrams for RGB color spaces show the D65 illuminant as a white point. White point is where all three primaries are equal in intensity, so it is a neutral color at every luminance level.
What about D65? ... is it an exactly neutral color illuminant?
Or, it means that, if we look at the chromaticity diagram under the illuminant D65, the white point of the color space takes the color of this illuminant and for this reason, white points are labeled as D65 in chromaticity diagrams?

AttilaHan wrote:
Ok, my question was ... D65 illuminant is really a neutral color?…
Of course not—by definition:
CIE Standard Illuminant D65 (sometimes written D65[1][2]) is a commonly-usedstandard illuminant defined by the International Commission on Illumination (CIE).[3]It is part of the D series of illuminants that try to portray standard illumination conditions at open-air in different parts of the world.
D65 corresponds roughly to a midday sun in Western Europe / Northern Europe, hence it is also called a daylight illuminant. As any standard illuminant is represented as a table of averaged spectrophotometric data, any light source which statistically has the same relative spectral power distribution (SPD) can be considered a D65 light source. There are no actual D65 light sources, only simulators. The quality of a simulator can be assessed with the CIE Metamerism Index.[4][5]
The CIE positions D65 as the standard daylight illuminant:
[D65] is intended to represent average daylight and has a correlated colour temperature of approximately 6500 K. CIE standard illuminant D65 should be used in all colorimetric calculations requiring representative daylight, unless there are specific reasons for using a different illuminant. Variations in the relative spectral power distribution of daylight are known to occur, particularly in the ultraviolet spectral region, as a function of season, time of day, and geographic location.
—ISO 10526:1999/CIE S005/E-1998, CIE Standard Illuminants for Colorimetry
http://en.wikipedia.org/wiki/Illuminant_D65

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Using white point for White Balance (instead of gray point)

Dear All,
I am looking to buy Aperture 2.0, but one point annoys me a bit : it seems that we can only use gray point to make a White Balance. I use to use only white points in Photoshop, as my photos of products rarely include gray colors. I take the photos on white background only, and when doing WB with a white point, my product gets nice colors, and more important, appears to "float" on a totally white background.
Also, I do not want to bother with a gray card, as by experience it didn't prove to be as effective.
My question is : is there any means or plug-in to use white point to make a white balance ?
Thanks a lot !
Arn'

Arn,
Hate to break it to you but.... It doesn't matter if you use white or grey as long as the actual color is neutral (no tendency towards blue etc.) what does matter regarding white is to make sure that there is enough color information in all the color channels to make an accurate assessment of the color of the light in the scene.
As there are a million ways to do something in PS I don;t know exactly what you are doing but it sure sounds like you are actually doing a couple of things to the image in one step. In Aperture if I assume you are using the white balance control brick to manipulate white balance that is the only thing that is being changed - nothing else (like the contrast).
RB

White point selection when profiling monitor

When profiling monitor, many sources say that begin with the native white point of monitor and then compare different white points in order to find best working white point selection for your ambient conditions.
There is an option in i1Display Pro and you can specify the target white point as the CCT of ambient lighting conditions.
I decided to try this one ... and I calibrated my monitor exactly what the instructions said, but at the end I got completely unrelated achieved CCT as seen in the following image.
I would like to learn the reason for such a unrelated finish.
My second question: From the point of view of color theory, what do you think about specifying the target white point as the CCT of ambient lighting?
And, my last question: I've got contrast ratios approximately 1:700 from my previous measurements, but now it said that it is 1:425 as seen in the image ... what do you think about such a great difference from a measurement to a measurement?
Thanks a lot ...

Hi Don,
6.0.5 is now available. 6.0.5 fixes this bug. Sorry for your troubles.
Mac:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=5630
Win:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=5631
Peter Garaway
Adobe
Premiere Pro

My older ibook g4 is locked up with an icon flashing. looks like a file folder flashing a blue and white face/question mark. what is this?

my older ibook g4 is locked up with an icon flashing. looks like a file folder flashing a blue and white face/question mark. what is this?

Apple's suggestions for dealing with the flashing question mark folder:
http://support.apple.com/kb/TS1440?viewlocale=en_US
Niel has summed it up pretty nicely.

Setting white point in LR

I'm almost sure I'm missing something but I cannot find a solution. I'm using LR (currently 2.2) for quite a while (since 1.2) but I simply cannot find an easy, user friedly and predictable way how to set a white point of edited pictures.
In PS, CR, DPP and most other editing SW and RAW processors, there two typical easy tools how to set the white point.
1) a white point picker which (when used) defines a desired tone as white and the relevant SW then redistributes the tones accordingly;
2) in "levels" or "curves" dialog (or their equivalents it is possible to move the "White level" treshold below which the remaining tones are redistributed accordingly - the iterface varies (sometimes it is the border of the histogram or curve diagram that can be moved (DPP), sometimes it is the slider in histogram or curve diagram setting this limit
botw ways generally lead to the same and quite uniform result. I.e. I'm usually able to get almost identical result by setting white point in PS, DPP, CR, .... and other SW by such simple operation when working over identical picture data.
However in LR it is virtually impossible to achieve similar result in LR. No white point picker, no slider enabling setting the white limit, no chance to move borders in the histogram chart. The only available tools for this purpose are
"Exposure" and "Brightness". None of them providing for the desired functionality alone - their combination giving sometimes acceptable but hardly predictable results (definitely not as predictable as achieved e.g. in PS by simple and single move of white limit slider in "level" dialogue or equivalent step in CR.
Do I really miss something important (I hope so) in this respect or is LR completly lacking this (for me really core/basic) functionality present in all other photo and RAW editting SW I know - even from Adobe?
thanks

I agree with the original poster - I find it troublesome to set the white point in an image. In a situation where a traditional (PS, Aperture) levels control would make it convenient to push a particular tone to white, I find myself going back and forth between exposure and the tone curve a fair amount. Another description of what I want, effectively, is a 'recovery' slider that goes up as well as down.
(See end of post for replies to a few specific points.)
An example:
Here is the original image, with its histogram and tone curve - black to middle gray:
I want to push the small hatch/door to white, but that also overexposes my middle grays (I haven't yet touched the tone curve):
So now I go to the tone curve, and pull down both darks and lights:
However, at this point I've lost my whites (they are not quite clipped any more); and probably more importantly, since the tone curve is at the extreme low values, I have little working room or control.
Rather than working together or providing complementary functions, in this case exposure and the tone curve, to me, seem to be fighting; it requires back-and-forth to get the desired effect.
(To be clear, most of the time - that is, when my white point starts out more or less where I want it - being able to drag the histogram and smoothly-transitioned segments of the tone curve is brilliantly easy and useful. It's specifically the exposure control's nonlinear behavior/effect that I dislike, as it makes it difficult to adjust near-white tones.)
Responding to specifics:
> Also, hold the ALT key (David Edwards)
Cool! (However, not a fix for this issue.)
> the controls themselves are not linear (Lee Jay)
> attempts to preserve highlights (Lee Jay)
> the exposure slider is almost exactly equivalent to the white point slider in Photoshop's levels/curves (Joa V. L.)
I think this is the root of the issue, for me - the exposure control is being intelligent in a way to protect hilights, which is counter to my intent. My experience leads me to disagree strongly with Joa's comment (though I would be very happy to discover I was wrong) - my problem is specifically that adjusting exposure up (brightening the image with exposure) affects tones less, the brighter they are.
> I need to decrease the Brightness (Henry_Deer)
> you may need to generate a higher-contrast tone curve and work with that (Lee Jay)
The brightness adjustment seems analogous to my use of the tone curve, though it's an alternate approach I haven't tried. However, both seem to suffer from the 'several rounds' problem.
Edited to reply to a few specific points

Colour Calibration / White Point setting - Is Imac Display really professional quality

I am trying to calibrate my imac 27" using i1 Display2 calibration software. I am trying to set a traget of 6500 using the software but it advises the current is only 5600 and suggests moving the RGB sliders to get this current white point up to my 6500 target. Unfortunatly i have no idea where i find these sliders on my imac. Can anyone advise how i change my current white point to get to the 6500 target?
Also, on the brightness issue, does shades work to reduce my brightness or will it simply interfere with my colour calibration?
Finally, i was going to use my iMac for professional photography. (Mainly on line but some print work required). Honestly, is the iMac display up to the job or should i consider changing
Thanks
Gary

Corbybhy, the glossy screen is the biggest and silliest myth out there. Really.
I have been a professional art director & designer for over 26 years, and by the way, for many years my high end professional CRTS were made of glass (and glossy). Another myth is that the screens cannot be calibrated, and are too bright. Hogwash. I use Spyder3Pro and have had few problems, guessing your device will be the same. Actually, the monitors seem to stay consistant for a heck of a lot longer than the old high end CRTs did. In the old days, most professionals calibrated to 5000k, but these days 6500k is the standard.
The amount of MISINFORMATION that is being spewed always amazes me. If you can keep your lighting consistant and somewhat dim, your life will be easier. Reflections are simply not a major issue, and are also overblown as a issue (by the way, my iMac sits next to a window, I just use shades to dim the ambient light).
I work mostly in print, and produce mostly publications, advertising & marketing materials. I have ZERO issues with my screen matching my proofs. ZERO. I do a huge amount of imaging, retouching & post-processing... all from my 27" iMac.

Setting a White Point and Black Point

I would like to suggest for future versions of lIghtroom to have an ability to set the white point and black points similar to levels and curves in Photoshop. This would be in addition to setting middle grey in the white balance settings currently in Lightroom. I find that the method of using Threshold to find the closest white and black pixels and then using these points to set the black and white points in curves or levels provides a better way to fix a color cast than the methods available in Lightroom.

MB,
There is no real need for Black and White point eyedropper type tools in Lightroom. By holding down the Alt key while changing the Blacks or Exposure sliders the display will show the areas that are being clipped. This is much faster than looking around for the darkest and lightest areas manually. If you just like to click to taste (like using the White balance dropper) then forget the Alt key and just move the sliders until you get the desired look.
Remember that the problem with Photoshop is that there are so many ways to do the same thing that it has become difficult and bloated. Lightroom strives to keep the interface as clear as possible.

Establishing White Point and Black Point

Hi,
How do I Establishing a White Point and a Black Point in Lightroom 1.4.1 and especially in Lightroom 2 Bata?
Thank You,
Hersul

The last post by OP might have closed this thread, but given the relative lack of activity on this and LR2 forums (summertime?) - I'll go a little deeper.
i White point
- If your white balance is right from the start, you just use the Exposure slider to set the white point. If not, first set the white balance - that effectively sets a preliminary white point for each channel separately, or, to be more precise, matches the right side of the histogram for each channel - then set the Exposure. So, with the white point you have complete control over the histogram, as well as over each channel.
i Black point
- here the situation is different. You can move the left side of the main (composite?) histogram using the Blacks slider, but there's no means for moving channels separately. In theory, with digital capture, there probably should not be need for this, blacks should be always black, so that's OK, but...
I once had a batch of pics scanned from film. The film was poorly developed so it has some strong brown-magenta cast in the shadows. In Photoshop it was a piece of cake to set the black point by dragging the left ends of each channel to the left edge of the histogram (heck, even Auto Level did a wonderful job). In Lightroom, there's just no way you can correct this, because you can't control the channels separately.

Change preferences for Auto black/white point in Camera RAW

Hey guys,
By hold shift and clicking on the slider for whites Camera RAW automatically sets the white point, same goes for the black. However, it always gets pushed to 255 (white).
Is there some way that you can edit this preference?

I don't know, but somebody may know for sure over in the camera raw forum:
https://forums.adobe.com/community/cameraraw

Setting White Points in Camera Raw

When setting white points in Adobe Camera Raw, while holding down Alt (on a PC), are the red marks what I should look for? Because white marks also appear? Which ones are relevant for the white point?

ACR doesn’t work that way. There is an eyedropper for the overall white-balance that you can set by clicking on a relatively bright, neutral area, but there aren’t black and white-point eyedroppers. But, what is clipped black or white is determined by the output colorspace you have set at the bottom and you can get some idea of what will be clipped black and white by turning on the clipping indicators and watching for the areas you’d be eye-droppering on (the black and white patches in your grayscale) to start showing the clipping color overlay for black and white, but any further toning adjustments will move data in and out of what is darker than black and lighter than white so what is clipped for output will change as you fiddle with the various toning sliders.
The reason things are different: In PS, when you set a black-point and white-point in Levels and click Ok, the data below and above those is thrown away and that is the starting point for the next adjustment. In ACR, things are non-destructive and all the adjustments occur simultaneously, rather than sequentially as in PS, and no clipping occurs until you create the output file. This means that the pixels that are darker than your black-point and lighter than your white-point are still there, and can be moved into the black-to-white range if you do further toning adjustments. Having more headroom of the pixels that are outside the black-to-white range is good because you won’t get the posterization or banding that occurs when colors and levels are clipped after each adjustment in PS.
Can you describe what you intend your overall workflow to be on an image: how much adjusting will occur in ACR and how much, if any, might happen in PS, after the image is opened into PS from ACR, or opened from a file saved from ACR? There might be other ways to approach what you’re trying to accomplish.

Setting black and white points

Dear friends,
I am shooting some pics with a "Whibal like" target card which has a white, black and 18% neutral grey shades.
In Camera Raw I I can easily correct the white balance with the provided eyedropper on the top row by clicking on the grey target.
I cannot find any way to set the black and the white points though and have to resort doing that for EACH picture in Photoshop via a levels or a curves adjustment layers.
It would be great to be able to set those in Bridge/Camera Raw so that I can then copy those settings to other similar shots.
Any ideas ? Thank you
Marco

I am having the same problem, although its now Camera Raw 7 - where can you set the white, mid, and black points in Camera Raw with the eyedropper tool. It seems you have to create a new psd file in Photoshop to do this, which does not make much sense since it is a basic levels adjustment. I am batch editing a bunch of CR2 files, and I just need to select the black, mid and white points on a grayscale that I've shot in the images - is there a way to do this in Camera Raw 7? Thanks!!

White Point Presets?

Hello all, I am using the trial version of Aperture2 and so far, I really like running a native pro image editor. I was using Lightroom (still am, mainly at the moment), and it has built in white point presets (daylight, shade, tungsten, etc). Does Aperture have this too? I was looking and I have to admit I haven't looked too thoroughly, but it's not so easy to find if it's there.
Thanks for any help you can offer!

there are no built in white balance presets... but you can create your own ...
here is a post on a blog that i used to make my white balance presets ...
http://blogs.oreilly.com/aperture/2006/11/create-your-own-white-balance-1.html

Setting the white point and gamma

I've heard that when calibrating your display you should set the white point and gamma to native. What is the difference between setting the white point at 65k and the gamma at 2.2?
Thanks in advance for your time
Rick

The difference would depend on what the native points were to begin with.

Setting the Black or White point in LR Mobile

In desktop LR, you can hold down the Alt (Option) key while moving the Black or White Slider in the Develop module to set the Black Point or White Point. Is there an equivalent action in LR Mobile? What is it?

Slide the Black or White Slider in Lightroom mobile with two fingers instead of one.

Floating point question

I am trying to create a price attribute, so I need to places after the decimal point. I how do I set that when I create a table?

Example from Help section in Oracle SQL Developer:
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the OLAP and Data Mining options
SQL> set serverout on
SQL> DECLARE -- Declare variables here.
2    monthly_salary         NUMBER(6); -- This is the monthly salary.
3    number_of_days_worked NUMBER(2); -- This is the days in one month.
4    pay_per_day            NUMBER(6,2); -- Calculate this value.
5 BEGIN
6 -- First assign values to the variables.
7    monthly_salary := 2290;
8    number_of_days_worked := 21;
9
10 -- Now calculate the value on the following line.
11    pay_per_day := monthly_salary/number_of_days_worked;
12
13 -- the following displays output from the PL/SQL block
14    DBMS_OUTPUT.PUT_LINE('The pay per day is ' || TO_CHAR(pay_per_day));
15
16 EXCEPTION
17 /* This is a simple example of an exeception handler to trap division by zero.
18     In actual practice, it would be best to check whether a variable is
19     zero before using it as a divisor. */
20    WHEN ZERO_DIVIDE THEN
21        pay_per_day := 0; -- set to 0 if divisor equals 0
22 END;
23 /
The pay per day is 109.05
PL/SQL procedure successfully completed.
SQL>It's not create table statement which you need but one can see in this example answer on your " Floating point question".
HTH
Message was edited by:
Faust

A white point question ...

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