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Author Topic: Prints too dark but monitor calibrated  (Read 15355 times)

Thenolands

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Prints too dark but monitor calibrated
« on: September 06, 2017, 01:07:42 am »

I am doing some amateur art reproduction work but my prints are coming out too dark. Before 1000 people post telling me my monitor is too bright let me explain my setup. Shooting with Pentax 645z, printing on ipf8400, screen calibrated with Spyder 5, exposed the image according to in-camera light meter using gray card in same light as artwork, using custom color profile created using colorchecker passport. I feel like my monitor and print match pretty well but my issue is why is it too dark if I am not editing the photo and it is supposedly a properly exposed image? Again, I am not viewing on a bright screen and reducing the exposure in post. I am not adjusting exposure at all. It doesn't seem like I should have to increase my exposure in post production just to get a proper image printed.
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BobShaw

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Re: Prints too dark but monitor calibrated
« Reply #1 on: September 06, 2017, 01:33:25 am »

Could be lots of things.
First is it correctly exposed? If you don't know if it correctly exposed then you are on the back foot. What does the histogram show? Is the histogram for the grey card image in the centre of the histogram? Did you adjust levels or something similar? As you move the mouse over the image do the highlights read about 220+ on the Digital Color Meter or in the application?
At the end of the day, if the subject is dark, the print will be dark.

Also there is no such thing as "amateur art reproduction". There may be reproduction of amateur art, but Art Reproduction is a complex thing.
« Last Edit: September 06, 2017, 02:02:11 am by BobShaw »
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Dave Rosser

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Re: Prints too dark but monitor calibrated
« Reply #2 on: September 06, 2017, 07:08:18 am »

I am doing some amateur art reproduction work but my prints are coming out too dark. Before 1000 people post telling me my monitor is too bright let me explain my setup. Shooting with Pentax 645z, printing on ipf8400, screen calibrated with Spyder 5, exposed the image according to in-camera light meter using gray card in same light as artwork, using custom color profile created using colorchecker passport. I feel like my monitor and print match pretty well but my issue is why is it too dark if I am not editing the photo and it is supposedly a properly exposed image? Again, I am not viewing on a bright screen and reducing the exposure in post. I am not adjusting exposure at all. It doesn't seem like I should have to increase my exposure in post production just to get a proper image printed.
I find Canon Printers print dark at default settings. You can adjust print brightness in the printer driver,  I find I have to apply 20 brightness adjustment to my Canon Pro 100 to get a satisfactory print brightness even though I have a fully colour managed workflow. If you are using Lightroom you can adjust the brightness in the Lightroom print module rather than the printer driver.
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nirpat89

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Re: Prints too dark but monitor calibrated
« Reply #3 on: September 06, 2017, 08:11:01 am »


I am doing some amateur art reproduction work but my prints are coming out too dark. Before 1000 people post telling me my monitor is too bright let me explain my setup. Shooting with Pentax 645z, printing on ipf8400, screen calibrated with Spyder 5, exposed the image according to in-camera light meter using gray card in same light as artwork, using custom color profile created using colorchecker passport. I feel like my monitor and print match pretty well but my issue is why is it too dark if I am not editing the photo and it is supposedly a properly exposed image? Again, I am not viewing on a bright screen and reducing the exposure in post. I am not adjusting exposure at all. It doesn't seem like I should have to increase my exposure in post production just to get a proper image printed.

Agree with Bob on reproduction photography being a very difficult thing.   A project taking pictures of antique wall papers once made me realize how much.

With the problem at hand, my sense is that the mismatch is something to do with the use of the grey card. The grey card, used conventionally in the way it was used in a film camera, will symmetrically push the exposure within the dynamic scale of the film or the sensor.  The result is that the photograph is "properly" exposed, but it is "correctly" exposed?  I would say it depends on how you light up your subject.  If you do an experiment and vary the amount of light falling on your painting (I am assuming that's what your are reproducing) and take several shots each using the grey card as your exposure guide, the resulting photographs will all look the same.  So even though you made no change in post-processing, only one of those photograph, if that, will match the intensity of the original subject.  So by not doing any editing, you actually end up with an inexact reproduction.  In your particular case, you got darker outcome because the artwork is well-lit, as usually is, and the camera wants to normalize it to 18% grey.  Looking at it another way, if you take a picture of a dark room using grey card, you end up with a light room.

Considering that there is no mismatch between the monitor and the print, you can pretty much use the monitor to do the final adjustment.  Light your painting as it would normally be lighted in display where you can see it side by side with your monitor, preferably with the same color temperature as your monitor calibration.  Then using something like Levels adjustment with the middle grey slider, darken or lighten to match the monitor and the painting to your satisfaction.  Print and hopefully you will be much closer than before.

Does that make sense?

:Niranjan.
« Last Edit: September 06, 2017, 08:17:08 am by nirpat89 »
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Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #4 on: September 06, 2017, 08:23:51 am »

@BobShaw: I get it is complex. That is why I am in the newbie section asking questions. To your other comments, to get a histogram of the gray card I assume I have to take a shot containing only the gray card or can I crop to include only the gray card?

@Niranjan: forgive me but I thought the point of the gray card was to eliminate the fact that the light sensor in camera wants to make everything 18% gray and thus normalize the exposure regardless of how well or dimly lit the subject is. No? If not, are you saying I should back the lights far enough off the art that it is not so intensely lit? I am afraid this would result in poor light coverage of the piece (again, I don't have a $100k setup)

Also, failed to mention that I already have +20 brightness selected in Lightroom just to get print to match monitor. With the painting I am currently working on, I got the print to match just about spot on (to my amateur eye) when I increased the exposure in Lightroom by 1.0. That seems to be ALOT to me. So,one, I don't feel that should be necessary to match the print and two, I worry about artifacts similar to high ISO if I am constantly artificially boosting exposure
« Last Edit: September 06, 2017, 08:39:51 am by Thenolands »
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farbschlurf

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Re: Prints too dark but monitor calibrated
« Reply #5 on: September 06, 2017, 09:09:08 am »

You might be interested in this
https://www.dpreview.com/forums/thread/2938408#forum-post-37440432
scroll down a bit.
Actually I started to use a lightmeter for such tasks (which were much more amateur-like, than yours ...)
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nirpat89

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Re: Prints too dark but monitor calibrated
« Reply #6 on: September 06, 2017, 09:13:32 am »

Use of grey card and taking a reading and calculating the exposure is not very different from the camera taking readings at many different spots (based on settings chosen,) averaging it and calculating the exposure.  The latter is simply based on a variety of colors and points of different reflectivities rather than just one (grey) color and 18% reflectivity.   Both, if done properly, try to put the image within the capability of the film or the sensor without caring for what the scene looked like.

The way I would do is ditch the grey card (unless it is color neutral and you are using it to correct the color-cast in post, in which case you can just take a separate picture of it) and use the camera histogram as your guide for exposure - making sure the it does not exceed on either side.  You do not have to compromise on the light, do the best you can so get a even exposure without reflections.  Then adjust the level of brightness in an application by comparison with the artwork lighted in the same way as it would in normal viewing circumstances.  The last step is not to rectify the failure of the exposure but necessary to arrive at the correct brightness level for viewing.
« Last Edit: September 06, 2017, 10:42:45 am by nirpat89 »
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Christopher Sanderson

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Re: Prints too dark but monitor calibrated
« Reply #7 on: September 06, 2017, 10:14:09 am »

Quite often the 'My print is too Dark! problem' is caused by perception - especially if you are judging the file brightness against a black background on your profiled monitor and then using a white border or mat for the print. You might start by changing the background against which the file is seen in Lightroom to White and reducing the size displayed so there is lots of white surround.

Let's try to diagnose the issue. Would you please take a screen grab of the histogram of the actual file that you are printing (not the camera original). Also if you know how*, use the LAB read-out in Photoshop to measure the brightness (L) of various tones within your file, picking an 'average' light tone, midtone and darktone. Let us know what the readout is. Just give us the L readout for now and ignore the a b

* Control/Right click the eyedropper in the Info palette

It is possible that a simple curve adjustment is all that is needed.
« Last Edit: September 06, 2017, 10:18:50 am by Chris Sanderson »
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Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #8 on: September 06, 2017, 12:06:35 pm »

I will work on uploading a pic today.

On a semi-related note, for those of you who do some art reproduction work, if you have a customer that wants a print of an oil painting printed on canvas, do you go with a luster coated canvas or matte? Luster always seems to have far better vibrancy and depth similar to the oils painting but it seems many of the quality canvases available are matte.
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HSakols

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Re: Prints too dark but monitor calibrated
« Reply #9 on: September 06, 2017, 03:23:27 pm »

In this video Charlie Cramer talks about prints and perception.  He also gives some great examples.
https://www.onlandscape.co.uk/2017/08/charles-cramer-landscape-photography-conference/
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nirpat89

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Re: Prints too dark but monitor calibrated
« Reply #10 on: September 06, 2017, 03:49:01 pm »

On a semi-related note, for those of you who do some art reproduction work, if you have a customer that wants a print of an oil painting printed on canvas, do you go with a luster coated canvas or matte? Luster always seems to have far better vibrancy and depth similar to the oils painting but it seems many of the quality canvases available are matte.

I haven't done reproduction work but do make prints on matte canvas which at times I brush with a acrylic water-based gloss varnish that imparts luster to it while also giving it a little more depth.  It is good for protection as well.  Something you can experiment with in lieu of a luster canvas. 
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Christopher Sanderson

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Re: Prints too dark but monitor calibrated
« Reply #11 on: September 06, 2017, 05:59:45 pm »

In this video Charlie Cramer talks about prints and perception.  He also gives some great examples.
https://www.onlandscape.co.uk/2017/08/charles-cramer-landscape-photography-conference/
We will soon be publishing a new video project in the Masters series in which Charlie Cramer gives an expanded version of this lecture. There will be a detailed chapter on Perception.

Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #12 on: September 06, 2017, 07:42:34 pm »

okay, going to try to attach screen shots of the histogram of the entire painting and just the gray card. I see the gray card is shifted slightly to overexposed? is that right? so that may make it expose darker? Also attaching histogram of increasing the exposure in post to 1.0 (1 stop?) which prints perfectly and the histogram would tend to agree, no? so what is causing this?

Sorry, this is actually my first time diving into the histogram so don't make too much fun :)

I should also say i am using a custom color profile based on the colorchecker passport if that makes any difference. Just for fun i removed it and used Adobe Standard and of course it changed the histogram but did not shift significantly toward better exposure.
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Christopher Sanderson

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Re: Prints too dark but monitor calibrated
« Reply #13 on: September 06, 2017, 09:56:18 pm »

It appears that in the original exposure, the vast majority of tones are darker than 50% gray. This suggests that the shot was under-exposed and the print will certainly appear dark without correction. The third screenshot with a one stop increase in exposure certainly looks better. On printing with that correction, how does it compare to the original?

Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #14 on: September 06, 2017, 10:08:37 pm »

The 1 stop increase printed near perfect. So, if the light meter read a correct exposure off the gray card, and I didn't change the camera settings and then took my shot, why would my in-camera light meter be off by a whole stop? Is it possible that the in camera light meter is that bad on a 645z? Or is there something in my process that is wrong?

Please don't assume that I did or did not do certain things. I am fairly new at all of this and could be screwing up anywhere, really 😀
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BobShaw

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Re: Prints too dark but monitor calibrated
« Reply #15 on: September 07, 2017, 02:14:19 am »

okay, going to try to attach screen shots of the histogram of the entire painting and just the gray card.
I should also say i am using a custom color profile based on the colorchecker passport if that makes any difference.
That is not a grey card. As you now advise, it is a colorchecker passport (CCP). So ignore my previous comment on reading the RGB value of the "grey card".
However you do have a tool suitable to do reproduction if you know how to use it. There are White squares on the CCP, they need to be white. Not off white, light grey, dark grey etc.
On your middle photo the white squares are at best mid grey. You need to raise the exposure until these are at least 220 RGB value.

Buy yourself an incident light an flash meter. A cheap one like Sekonic 308 is fine. You can do without it amateur style by taking lots of shots until you get it right or just measure it once. Once you have plenty of experience you may not use it much, but at least you will understand why the camera reading is always wrong unless you are reading the reflected light from a totally grey card. That is all they are calibrated for.

Have a look at these. They are for Hasselblad but will give you an idea. You may buy a Hasselblad after watching.
https://www.youtube.com/watch?v=fxEDn4ueFJE
http://www.hasselblad.com/products/phocus-2-9-colour-calibration/

good luck
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Christopher Sanderson

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Re: Prints too dark but monitor calibrated
« Reply #16 on: September 07, 2017, 09:20:13 am »

There has been some good advice given here - probably enough for you to now succeed.

On an anecdotal level, I have always found that the basing of exposure/white balance on a gray card or colour checker to be problematic. This likely has to do with my method and the various things that can go wrong between subject, card and exposure. The inference of a colour checker is that it will solve all problems but that alas is far from true - in my experience it gives little more than a guide.

I tend therefore to work on the KISS principle and simply use the simpler methods of my eyes and the numbers that the histogram and the file give me. No, not terribly scientific but if one's method is faulty, a lot less frustrating. I still suggest learning how to use the LAB readouts from PS and LR. These are simple to understand and provide excellent information on your file.

digitaldog

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Re: Prints too dark but monitor calibrated
« Reply #17 on: September 07, 2017, 10:21:44 am »

Sorry, this is actually my first time diving into the histogram so don't make too much fun :)


Everything you thought you wanted to know about Histograms


Another exhaustive 40 minute video examining:


What are histograms. In Photoshop, ACR, Lightroom.
Histograms: clipping color and tones, color spaces and color gamut.
Histogram and Photoshop’s Level’s command
Histograms don’t tell us our images are good (examples).
Misconceptions about histograms. How they lie.
Histograms and Expose To The Right (ETTR).
Are histograms useful and if so, how?


Low rez (YouTube): http://www.youtube.com/watch?v=EjPsP4HhHhE
High rez: http://digitaldog.net/files/Histogram_Video.mov[/font]


Use a color reference image not your 'dark' image to test this!
http://www.digitaldog.net/files/2014PrinterTestFileFlat.tif.zip
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Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #18 on: September 07, 2017, 11:30:11 am »

Thanks for all the replies. It is very helpful. i am going to take some more shots of that painting tonight and see how it goes.
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Thenolands

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Re: Prints too dark but monitor calibrated
« Reply #19 on: September 07, 2017, 08:09:51 pm »

If you had to choose between 55mm or 120mm macro on the 635z which would you choose for art reproduction? I know, I know... you wouldn't, you would use a hasselblad... but if you had to?
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