monitor calibration

[jkshyt]

Hello, I'm using an acer vg270 monitor and my images seem darker when I print or lighter when I notice an edit correction on the CIC. I'm assuming I should calibrate my monitor.

I've tried to adjust using the advice on here and I my efforts don't seem to work.

Any suggestions please?

TIA

[DanK]

Jack,

When people talk about calibration, they are usually talking about getting colors correct. That's a different problem than you are having.

Comparing the brightness on a monitor to the brightness of a print because the monitor is emitting light, while the print is only reflecting it. And they will be affected differently by the level of ambient light. Turning up the lights makes a print look brighter and a monitor look less bright.

To get some degree of control over this, you have to adjust the brightness of the monitor. Calibration software often has this option, but most monitors also allow you to control the brightness directly.

My suggestion is that experiment with settings in the range of 80 to 110 cd/m^2. You'll have to do this in a setting with a fixed ambient lighting level. Then compare the prints under lighting similar to what they will be viewed under with what you see on the screen.

Your results may vary. I believe Manfred, who is probably the most experienced printer here, uses 80 cd/m^2. I use 100 or even 110. I edit for prints only in the evening, when I can set the lighting level at the level I've chosen for editing. I no longer remember the ambient level I set, as I know where to set the dimmer to get that level. I think Manfred will have suggestions about ambient levels.

[Polar01]

Jack the factory setting for that monitor is 250 cd/m2 you would have turn the brightness down about half or a little more to get into 100 range. I have a x-rite that I use to help with the brightness.

Cheers: Al

[LenR]

Hi Jack, agreed regarding the monitor brightness. I have mine set at 80cd/m2. As suggested , experiment with the settings. Perhaps the attached may help........

http://digitaldog.net/files/Why_are_...s_too_dark.mp4

[Manfred M]

Dan has made a lot of good points. There are a number of inter-linked issues at play here. Let me try to cover the main ones.

Computer screen - the screen should ideally be at least 100% sRGB compliant. Unless this is stated in the spec, you can safely assume it is not. Most colour photo printers exceed the spec and are at least Adobe RGB compliant and are often well into even wider colour spaces (this depends on the paper being used and the ink set being used). Your screen does not list and colour space compliance, so I suspect it does not cover the sRGB colour space. It seems to be a gaming screen, so there are other factors (refresh time) that are more important than colour fidelity. The relatively low price point is another suggestion that it is not ideal for photography work.

Most screens that are straight out of the box have been set up to work well in a brightly lit office environment, not in a darker editing environment that is recommended. As Dan has mentioned, most sources suggest that a screen be set to between 80 - 120 cd/ sq m output. This value is set when using a calibrating / profiling device like the x-Rite i1 or Datacolor Spyder devices.

Moving on to calibration and profiling. This CANNOT be done by eye, requires one of the devices mentioned in the previous paragraph. There are two distinct steps. The first is calibration, which means making sure that the computer screen is set up properly; brightness, contrast and the appropriate illuminant model. As mentioned before, brightness should be set to 120 cd/ sq m output. In photography we tend to use the D65 illuminant, The second step is profiling, which means setting up the computer screen to display colours as accurately as possible. A screen that is not compliant with one of the colour spaces used in photography cannot be made compliant, but the colours that can be displayed are going to be as accurate as your screen can make them.

The other issue is room brightness. Ideally you should be working in a dimly lit room. It should be less than 70 lux at the work surface and if you can bring that down to below 40 lux, even better. That is not completely dark, but when your room is at that level, you still read printed material, but doing so will be a bit straining on the eyes. The reason for this low level of illumination is to get a decent contrast ratio on your screen. 1000:1 is generally considered good. When you first start working at these output and room light levels, your computer screen will look a bit dull, but you will quickly become used to it.

The other issue with printing is that you should be evaluating the print in the light that it will be displayed under. I work with test prints; depending on the size of the final print, I will make 4"x 5" or 5" x 7" prints of the image and will put these where the prints will be shown and work this way. Light levels can and do vary, so there are tradeoffs involved. Some people recommend making prints and evaluating them under a 150 lux light source (250 lux for gallery prints). The light source needs to give an accurate colour spectrum; a lot of fluorescent and LED lights are not particularly suitable.

I hope that this all makes some sense.

[Chataignier]

You might find this interesting :

https://photopxl.com/introduction-to...int-it-series/

[DanK]

The light source needs to give an accurate colour spectrum; a lot of fluorescent and LED lights are not particularly suitable.

This opens a can of worms, but to preface this, it has nothing to do with the original question, which is about brightness, not color accuracy.

Most fluorescent lights are awful in terms of color accuracy.

LEDs vary a lot. It's now common to give the CRI (color rendering index) values as well as the color temperature in marketing LEDs. A common value for inexpenive bulbs is 80, which is quite poor. Better bulbs are usually at least CRI=90. The Soraa Vivid BR30 bulbs I use are CRI=95.

However, that doesn't get you home free. The basic CRI metric excludes a number of colors, including deep red. (I've heard but never verified that the manufacturers pushed for this because of their inability to handle deep reds with fluourescent bulbs). The most important of the missing values is the deep red R9. Most inexpensive bulbs don't even have that spec provided. The bulbs I use are R9=95.

There are other metrics too, but you'll rarely see them except for high-end bulbs. If you can get a high CRI and R9, you probably have a good bulb. If you splurge on a high-end bulb like the ones I use, you will probably get a spec sheet with more measures. Here are the ones from my bulbs:

CIE Metrics: CRI 95, R9 95
TM30 Metrics: Rf 90, Rfh1 90
Whiteness Index: Rw 100

Bulbs of this caliber are not only expensive; they are hard to find. When I converted my home, I was able to get this quality in BR30 (reflector) bulbs, but not in most other form factors. The hardest was the most common, A19, the standard small screw-based bulb. 40W equivalent is roughly 450 lumens, and when I converted my house years ago, CRI 80 was the best I found in that range. Carrying a print from a room with the good BR 30 bulbs to the CRI 80 bulbs, you can see a very big difference, particularly but not only in the reds.

But none of this affects the perception of brightness. For that, the key is the brightness of your monitor and the relative brightness of monitor and ambient light.

[Manfred M]

You might find this interesting :

I've been waiting for this to come out. Steinhardt and Schewe are very knowledgeable.

I look forward to the rest of the series, but this intro really did not say much.

[jkshyt]

Ok, I tried to adjust the brightness of the screen and gamma to better reflect the what I should be seeing.
I think I'm close, by making adjustments to the histogram and clipping points.

edited
023 by jk Sullivan, on Flickr

As Shot, unedited
023-2 by jk Sullivan, on Flickr

Before I made any adjustments the original exposure looked ok.
After tweaking the screen it seems to be underexposed.
your thoughts?

[xpatUSA]

Before I made any adjustments the original exposure looked ok.
After tweaking the screen it seems to be underexposed.
your thoughts?

Jack, in my pedantic world, "exposure" means how much light the sensor receives when a shot is taken, namely how many lux for how long a time. How bright a review image looks on your screen has little to do with exposure, IMO.

For example, I could easily post quite a dark image developed from an over-exposed raw file and vice-versa ...

[Manfred M]

Jack, in my pedantic world, "exposure" means how much light the sensor receives when a shot is taken, namely how many lux for how long a time. How bright a review image looks on your screen has little to do with exposure, IMO.

For example, I could easily post quite a dark image developed from an over-exposed raw file and vice-versa ...

Pendantic but not following what the rest of the "experts" call it Ted. A quick look at software from Adobe, Capture One, DxO Labs and even GIMP all use the term "Exposure".

[DanK]

They are shorthand for “adjust as if exposed differently.” No different from other adjustments. If you increase saturation, you aren’t changing the saturation in the capture.


Sent from my iPad using Tapatalk

[xpatUSA]

When I lived in England, I always enjoyed a game of arrows (aka darts):



Meanwhile, three images from outside the pale, each with equal exposure for Jack to ponder:

.

[Manfred M]

Ok, I tried to adjust the brightness of the screen and gamma to better reflect the what I should be seeing.
I think I'm close, by making adjustments to the histogram and clipping points.

edited
023 by jk Sullivan, on Flickr

As Shot, unedited
023-2 by jk Sullivan, on Flickr

Before I made any adjustments the original exposure looked ok.
After tweaking the screen it seems to be underexposed.
your thoughts?

Jack - in your screen settings without doing these against a standard is not going to give you strong, consistent results. As a general rule, in photography we have our screens set to a gamma of 2.2 and use the D65 setting on our screens. Different industries have different standards; work for the offset press industry was based on a gamma of 1,8 and the D50 illuminant.

This process cannot be done visually (although there are many "tools" out there that claim to help. The human visual system (eyes / brain) makes things with slight colour discrepancies (especially when dealing with light sources that have different colour temperatures) look "correct". This process is called chromatic adaptation and takes just a fraction of a second to kick in. This is why everything we see "looks right" regardless of the light source. This catches us out when we try to do manual corrections to our computer screens and why people use the hardware I mentioned in thread #5 to achieve this.

You appear to be confusing two separate issues; the settings of your computer screen and the post-processing work done on an image. Ideally the screen is set properly so you can see what the tweaks to your images have accomplished. Your histograms, etc. provide good guidance in terms of knowing what you are seeing is accurate, based on having a computer screen that has been set up properly.

[xpatUSA]

Pedantic but not following what the rest of the "experts" call it, Ted. A quick look at software from Adobe, Capture One, DxO Labs and even GIMP all use the term "Exposure".

Manfred, with further thought about that, it is indeed a pity that they do. It shows that those people are dumbing it down for the masses, thereby causing the term "exposure" to pass into the lexicon of digital photography as also meaning "image brightness".

Not dissimilar to "ISO" now being thought of as sensor-sensitivity when it is no such thing.

Or "MP" being thought of as resolution when it ain't ... grump.

For me, it is a greater pity that the cognoscenti of these fora could think or talk of a too-bright image as "over-exposed"! Should we now also think of a blurry image as "out-of-focus"?

[Manfred M]

Manfred, with further thought about that, it is indeed a pity that they do. It shows that those people are dumbing it down for the masses, thereby causing the term "exposure" to pass into the lexicon of digital photography as also meaning "image brightness".

Not dissimilar to "ISO" now being thought of as sensor-sensitivity when it is no such thing.

Or "MP" being thought of as resolution when it ain't ... grump.

Ted - language is fluid and there are all kinds of terminology that inherently do not make sense in a strictly technical sense. Exposure is certainly one of them. It has become commonly used, so in my view the meaning has changed from the original and the new meaning is understood by most photographers.

My personal favourites are Dodging and Burning. Two techniques I used a lot in the wet darkroom to make local adjustments in exposure on a print. In dodging I would use either my hands or a small piece of cardboard that I had cut out or plastic shape that I would move around on the end of a thing wire to block the light from hitting the photographic paper that was being exposed. I would be moving the my hands or the piece of light blocking material constantly to prevent a defined edge from forming from the shadow it would cast. Dodging made sense as this movement looked like the photographer was dodging parts of the light beam coming out of the enlarger. In the current digital world, I prefer the term locally brightening an area.

Burning similarly had a physical process, again using the hands or a piece of cut out cardboard that was approximately the shape of the area where one would allow for longer exposure by blocking all the light coming from the enlarger except for the area that one was trying to locally darken. The process also required the pattern to be moved continuously to eliminate any sharp areas that would give away what had been done. As the areas became darker, there was a tenuous connection with charring the spot, hence burning did make sense. In the digital world, local darkening bears no resemblance to the physical process, but the terminology lives on.

Whenever I teach dodging and burning, I do get asked where the terminology comes from and people who have never worked in a traditional darkroom look very confused. On the other hand, if I use the word "exposure", everyone understands...

[xpatUSA]

Ted - language is fluid and there are all kinds of terminology that inherently do not make sense in a strictly technical sense. Exposure is certainly one of them. It has become commonly used, so in my view the meaning has changed from the original and the new meaning is understood by most photographers.

Manfred, if the meaning of exposure has changed from the original and the new meaning is now the brightness of the developed image, I am saddened even further. You have just voided the definition found in many photographic works - some even current!

I said: "causing the term exposure to pass into the lexicon of digital photography as also meaning image brightness" by which I allowed a different meaning for example that found in ISO standards.

My personal favourites are Dodging and Burning. Two techniques I used a lot in the wet darkroom to make local adjustments in exposure on a print. In dodging I would use either my hands or a small piece of cardboard that I had cut out or plastic shape that I would move around on the end of a thing wire to block the light from hitting the photographic paper that was being exposed. I would be moving the my hands or the piece of light blocking material constantly to prevent a defined edge from forming from the shadow it would cast. Dodging made sense as this movement looked like the photographer was dodging parts of the light beam coming out of the enlarger. In the current digital world, I prefer the term locally brightening an area.

Burning similarly had a physical process, again using the hands or a piece of cut out cardboard that was approximately the shape of the area where one would allow for longer exposure by blocking all the light coming from the enlarger except for the area that one was trying to locally darken. The process also required the pattern to be moved continuously to eliminate any sharp areas that would give away what had been done. As the areas became darker, there was a tenuous connection with charring the spot, hence burning did make sense. In the digital world, local darkening bears no resemblance to the physical process, but the terminology lives on.

Whenever I teach dodging and burning, I do get asked where the terminology comes from and people who have never worked in a traditional darkroom look very confused. On the other hand, if I use the word "exposure", everyone understands...

Now I'm wondering if Adams et al ever thought of messing with the development of an image (dodging, burning, time, chemicals, brushing, smearing, etc., ad naus) as changing it's "exposure"!

Maybe it's in here:

https://www.dzphoto.it/wp-content/up...eries-no-3.pdf

or maybe not ...

[Manfred M]

Now I'm wondering if Adams et al ever thought of messing with the development of an image (dodging, burning, time, chemicals, brushing, smearing, etc., ad naus) as changing it's "exposure"!

He was a master of dodging and burning and would often spend all day in his darkroom doing so. The whole reason he developed the Zone System is so that he would have a printable negative that he could abuse in the post-processing steps.

He was known for using chemical toning and bleaching as well, I believe. He was certainly not the only one to employ these techniques. Irving Penn certainly used the chemical treatments in his work for precisely those reasons, on the print, not the negative, so far as I can determine.

The ISO standards have their own language and that is definitely not what most of us who have a formal background in photography generally studied in the digital age. I know of a few instances in some of the full-time degree and diploma programs in photography back in the 1960s and 1970s, densitometry was part of the curriculum. So was toning and bleaching for B&W work.

[xpatUSA]

He was a master of dodging and burning and would often spend all day in his darkroom doing so. The whole reason he developed the Zone System is so that he would have a printable negative that he could abuse in the post-processing steps.

He was known for using chemical toning and bleaching as well, I believe. He was certainly not the only one to employ these techniques. Irving Penn certainly used the chemical treatments in his work for precisely those reasons, on the print, not the negative, so far as I can determine.

Thank you, but I wasn't really asking for education as to how they did their stuff.

The ISO standards have their own language and that is definitely not what most of us who have a formal background in photography generally studied in the digital age.

Might as well ignore ISO, then!

There you go again with "most of us" and now I feel quite seriously outside the pale of "convention".

One day I hope that we will come to some sort of agreement but, in this case, it seems that that is not to be.

I know of a few instances in some of the full-time degree and diploma programs in photography back in the 1960s and 1970s, densitometry was part of the curriculum. So was toning and bleaching for B&W work.

So, Manfred, since we can not agree and since no-one else seems to have an opinion on the matter, I'm done.

[Stagecoach]

So, I'll let you off the hook - since no-one else seems to have an opinion on the matter ...

I have an opinion.

Following and belonging to other forums the 'Exposure' word meaning often comes up and is discussed and argued for pages.

Those who most vehemently try to uphold that it should only be used with respect to aperture/speed or light hitting the sensor are in the minority. The consensus of opinion being, 'who cares', they understand fully what was meant.