Monitor calibration with Spyder 3

[akazoly]

Hi,
I have a Datacolor Spyder 3, and I would like to calibrate my Samsung 205BW

I'm using Mac OS X 10.6.4 and Spyder3Pro 4.0.2
One of my friends I talked to told me that it is better to calibrate the monitor using the RGB sliders, but I don't know if it is true.
I've also heard that is better to calibrate the display at night, when the only light came from a daylight bulb.

I decided to try this out, so here is what I did:
1. I set my monitor to the default settings which provided me the following:

- Brightness: 100%
- Contrast: 75%
- Red: 50%
- Green: 50%
- Blue: 50%

2. I also set the Spyder3Pro to use the RGB sliders.

3. Now, the welcome screen appears to show the following information:

I did everything, except: "Adjust the brightness to the level at which you are comfortable".
What does this mean? Do I need to reduce the brightness of my display before the calibration starts? (I think the default 100% is too high). Okay, I reduced the brightness to 80%

4. The ambient light was off by default and I turned it on
I'm was not sure about Brightness, so I decided to use 'Native'.

5. My ambient light reading is moderately low. The white point is 6500K. (I'm using a white daylight bulb - 30watt)
6. I placed the spyder3 on the display.

7. These are the RGB sliders.

My question: Do I need to adjust the brightness as well, or just the RGB sliders? (I reduced the brightness to 80% at the welcome screen as I mentioned before)

Do I need to obtain the smallest "Difference" value, 0.01 Dab ?
One of the problems I noticed is that I can obtain the smallest value, using different combinations of RGB values.

R: 34% G: 43% B: 55% gives 0.01 Dab
R: 44% G: 50% B: 37% gives 0.01 Dab
R: 33% G: 37% B: 23% gives 0.01 Dab

This is confusing.
Can you tell me more about how to allign these RGB sliders?
There is a rectangle. Do I need to align to the top line (1) or bottom line (2) ?

8. After the RGB adjustment, at a later stage the software ask me to adjust the brightness. Why do I need to do that? I'm pretty sure it breaks the RGB values I set before.

I would be grateful for any suggestions! Thank you!

 

[Garbz]

The brightness controls the screen's backlight brightness.
The red green blue sliders control the bias on the LCD output.

The idea between the sliders is that you put the red green and blue values between the two lines. They give you a range due to the fact that adjustments on some monitors are coarse and the fact that values drift. That and the idea of good colour is the point where you can no longer perceive the difference in shades. Many screens can get far more perfect than that, so you have a bit of a buffer to play with.

No with that out of the way.

a) why use a manual adjustment? This is legacy for displays or video cards which don't support DDC/CI. Most displays these days do, and this allows the software to control the sliders for you. That and for any digital display without an internal lookup table, the difference between calibrating using monitor adjustments, and calibrating using video card adjustments is non-existent.

b) Why adjust the sliders at all? What are you trying to match? Is it room lighting? The room lighting should be dark, in the order of 60-100lx. The brightest thing in the room should be your display. Your eyes will adjust to it's white point, which is why unless you're comparing your display to a print, or you have uncontrollable bright lights in the room the best white balance setting for your screen is "native". The justification for that is you have 8bits of data to work with, but if you need to bias your display to 6500k and your display is 2700k you end up with reduced values for red and green, in order to make your screen sufficiently blue. i.e. reduced quality.

One thing I don't get is why it's asking you what brightness you wish to have, despite selecting "legacy" in the options to begin with. Typically there should be no target brightness if you do that.

 

[akazoly]

I adjusted the RGB sliders until everything was close (color, kelvin, and brightness). Not just the bars in the middle:

After calibration I have a yellowish spot (shade) just in left corner of the screen. Altough, it's not really noticable I don't like it.

These are my RGB settings:

- Red: 39%
- Green: 45%
- Blue: 29%

Do you mean, I don't need to use RGB slider for my LCD screen ? (just the brightness and contrast controls?)

 

[KmH]

The Samsung 205BW uses the TN (twisted nematic) display technology which only allows limited accurate viewing angles likely causing the yellowish spot in the corner.

IPS (in-plane switching) displays offer much a broader viewing angle and are preferred for image editing.

 

[akazoly]

Thank you!
I set the monitor to the default factory settings (Brightness: 100% / Contrast: 75%). I can remove the yellowish spot reducing the contrast to 50% or increase it to 81%.

Altough, I heard it is better to calibrate with the default settings 75%

 

[Garbz]

I'm saying a) often monitors can be automatically controlled by the software so you don't need to set the RGB sliders, and b) for the most part if you set native colour balance you don't need to set this option at all. If your screen is bright enough then it won't matter thanks to your eyes adjusting to what the screen is showing as white. If you need to compare your screen against a print under calibrated lighting, or your room is bright, then you're back to square one.

 

[akazoly]

Dude, it doesn't matter how I calibrare I get the same yellowish spot in the upper left corner.
I think, the blue and the green cause this yellowish spot.

 

[akazoly]

I set the white point to "Native" instead of "6500K". It removes the yellow shade! finnaly!

 

[Garbz]

Yep, because now you're no long adjusting your blue and green bias.

 

[akazoly]

Does this have any side effect? I'm not looking for perfection, I'm just a hobby photographer.

 

[Garbz]

I mentioned it above. As soon as you adjust away from your native white point of the monitor backlight some colours end up with a reduced range of values to work with.

As for why a corner of your screen turned funny when you adjusted it? Dunno. Put it down to a cheap screen.

 

[akazoly]

Thank you!