Optimum brightness level of a lcd monitor

[2069]

hi,

 

i have a thinkpad laptop, the display is lcd. i noticed that with different

power-managing options (like 'optimum battery', 'max performance', 'ac power'

etc...), the display brightness changes.

 

i have been editing my images with 'save batter' preset...which makes the

display go dull...as a result the images look darker than they should...

 

what should be the optimum brightness level of a lcd display??

 

which makes me think...is photoshops brightness tool interchangeable with my lcd

display's brightness levels...i mean if the image is dark, i can probably up the

display level to make it brighter instead of doing it in ps...and vice-versa...

 

therefore, what's the differnce...i don't quite get it...

 

will appreciate if someone could explain...

 

thanks and regards,

 

anurag

[digitaldog]

Display luminance is based on the ambient light (and light color or color temperature)

you'll view your prints.

 

You need an instrument to calibrate the display and build a profile at such time, you'd

attempt to calibrate to the viewing environment.

 

http://www.ppmag.com/reviews/200604_rodneycm.pdf

 

http://www.ppmag.com/reviews/200605_rodneycm.pdf

[2069]

Thanks Andrew for the info.

 

I will probably never print most of my images...and i will be carrying around my laptop to different lighting situations while travelling...so basically its about the optimum appreciation of my images on my computer display.

 

my problem is that if i increase the display brightness, the lost shadow detail can be seen and images are no longer dark...something that i would be doing in photoshop....

 

It seems funny to keep changing the display brightness all the time...:)

 

regards,

[JAPster]

Dear AA...

I also have an IBM Thinkpad laptop, as well as a Gateway AMD Turion

64x2 laptop. The issue of LCD brightness is not as cut and dried as

one may think. For example, as you point out, your laptop has diff-

erent power modes, depending on how to use the laptop. For example,

while working in-transit, the laptop provides a 'battery saver' mode

that aims to reduce the system power-drain somewhat, and thereby

give you somewhat more time to run off battery. Likewise, there is

a 'full performance' mode, that provides all the power available to

the system, so each component can run at 100% performance, but in

this setting, the system sucks more current, so battery time is less.

Another factor is that you have LCD Brightness controls right

there on the keyboard, and you can manually adjust the LCD brightness

up or down, as you like it.

A third factor is the viewing angle that is formed, when you

position the LCD screen in front of you. If the LCD screen is a

true 90 degrees vertical, it may seem actually not as bright as if

it were positioned at, say 110 degrees. That extra amount of tilt

actually lines the screen up better with your plane of vision, and

so the screen appears brighter. (But, I think, in actuality, the

LCD screen is emitting the same amount of luminosity in either

position.)

A fourth factor is the level of light in your ambient environ-

ment, with a dimly lit room making your screen appear brighter

than it would look in a brightly lit room, or outside on a bright

day.

I also think that the human interpretation of colors involves

something of a subjective judgement. A full color image that looks

dazzling to one interpretter, with less experience, might look

rather normal to someone having lots more experience.

I think even the kind of eye-glasses one wears affects color

values in some ways. Not the actual color being reflected by the

subject, but the seeing of that color, as it enters the eye. For

example, polarized lenses alter the image colors, by removing

harsh glare from smooth surfaces.

And if you were to add a glare-blocking filter to your laptop

or external CRT, that too would alter the colors.

To further complicate the color viewing situation, the same

hi-res color image (still or video) is going to look just a little

different on different makes and models of laptops, CRT's,and

TV screens (CRT and LCD). For example, if you go browsing in

your favorite electronics store, stop and compare the images that

you see on different TV's, different laptops, and different CRTs.

Even when they display the same video or display image, what

actually comes out varies slightly from unit to unit.

Also, keep in mind that even when making adjustments in all

these different areas, none of these have anything to do with

the digital color information that is actually contained in a

hi-res color bitmap file. That information is digital, 0's & 1's,

and is a product of the color device, sensors, and firmware that

produced it. If you are using 32bit color display, then obviously

the laptop has a much much broader color pallete to select from

than if you are using something rudimentary, like 256 colors.

Finally, lets not forget that our eyes are not fixed static

photo-equipment that never changes. Our eyes are slowly changing

as we get older, and we simply dont see things the same way we

used to when we were much younger. I think this is especially

true as we pass into our 40's. I think also that the LCD screen

itself poses extra challenges to the human eye. I have a brother

who is an accomplished optometrist, and he told me that the eye

has to work significantly harder to focus accurately on a computer

image because the image itself is dynamic, constantly moving and

shifting. So the eye has to approximate a focus, rather than

acheiving a true sharp focus, as it would on a ordinary object.

 

So you see a number of factors come into play, before we even

start talking about modifying the color information that is

saved into the digital color file, using graphics software.

 

Based on these factors, I would offer some suggestions for

you to consider, and, if you think good, apply them to your

work situation.

 

1. Decide if you will be using the laptop, and doing work

on the color image files, only at home and/or at the office.

If you dont plan to edit color files while intransit (on a

plane, train, or bus)... then you can safely set the Power

Management setting to "Maximum Performance", since you will

be plugged into the wall AC power, and not from battery.

This setting will provide the most power to your LCD screen.

You can then adopt this setting as your 1st Personal Preference.

 

2. You've probably done this already, but set the laptop up,

in the room or office where you will be doing most of your

color work. Then spend a sufficient amount of time adjusting

things, until you get the screen image display to look the

way that you want it, using your very best judgment... You can

check and adjust these factors....

 

A. The ambient room lighting.

B. The LCD screen Tilt Angle.

C. The distance, from screen to Eye.

D. The screen brightness, using laptop keyboard control keys.

E. The display color systems, RGB vs CYMK.

F. Various display color standards, like Pantone.

G. The display resolution (horizontal & vertical)

H. The display color depth (256 colors, 16K, 24K, 32K)

I. The 'theme' that Windows uses to display window's colors.

 

You can check and tweak all these factors, until you arrive at the

best optimized combination that seems to deliver the truest and

most accurate colors to your set of eyes.

 

3. After adjusting these 'ergonomic' factors, pull up a sample batch

of your color images, and carefully go through a whole batch of the

color files. The aim here is to simply see how well the screen and

display system is going to render a wide range of real-world pictures.

You want to carefully review a whole range of color images. Then, if

you think the display image needs to be tweaked again, you can do it

after you have seen a pattern emerge from all the images. For example

if, after examining a whole batch of pictures, the screen display is

appearing a bit dark on all images, then you can tweak the Brightness

and make it a bit brighter.

 

4. Another idea is to actually measure the luminosity that is being

emitted by your screen while rendering a whole set of your files.

To do this, you'll need a Digital Light Meter, preferably one that

works well & is sensitive at low light levels. Set up your laptop

in your preferred work space, and go through the adjustment process

till you achieve the optimum looking images (to your eyes). Now

turn off all ambient lights, so that your LCD screen is the only

light source in the room. Then position the Digital Light Meter

a fixed and standard distance from the screen... say 12 inches.

Then go through a large batch of your sample files, and pull the

digital light reading given off by each image. Of course, some

images will be brighter than average, and will emit more light.

Other images will be darker, and will emait less light. But by

going through, lets say 100 of your sample files, you will be

able to quantify the actual brightness of individual pictures,

and then you can average the list, and get the Average brightness.

This number can then be used as a screen brightness Basepoint,

a fixed known value, good for that group of settings, and that

batch of pictures. If you use the digital light meter, its more

objective, since its providing you the reading it calculates, and

removes human subjectivity.

 

5. After you have gone through this whole process, and feel you

are getting good progress,and great images, you may want to selct

a very small number of pictures to use as your 'working color

standard files.' In other words, pick about 6 of the color images

that seem to best represent the type of images you work with, and

measure their brightness, using the method suggested above. This

will give the object luminosity of each image, on your system,

and with the settings that seem to give you the best image.

 

6. Finally, after you have achieved the best possible performance

from your laptop system, one that gives the best possible rendering

across a wide range of images, then go back and write down the

settings that you selected, to achieve that state. This document

is you backup list, and its better to write it down than rely on

memory. Save the document in a file, and keep that stored away.

Later, heaven forbid, if something happens to your laptop, and you

have to do s system rebuild, you will have that list handy, and

can then set all the settings back to the way you like them.

 

Lastly, unless you are trying to achieve a special effect using

the picture editing software, once you get your screen adjusted,

DON'T monkey with the settings. It can get very frustrating,

almost a trap, trying to adjust your display, on a picture by

picture basis. To me, it seems better to use a broad range of

your typical pictures, to achieve the optimum display, and

then work with that setup, the vast majority of the time. To

me, that approach would give you the most consistent image

quality, which includes brightness.

 

Anyway, I hope these suggestions will give you some help,

and perhaps give you some things to try.

AP

[2069]

thanks alan. thanks andrew. it all seems so complicated, with so many variables in play. will have to dig more and try understanding what's going on.

regards,

[iqbal]

Professor Peed: Your lecture is extremely valuable for many of us who encounter this challenge every day. Is it possible for you to SUMMARIZE them in a few critical steps, using only a few sentences for each step so that we can follow and practice. Thanks.