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Dynamic Range and ink jet photo printers
Now, I recently came across these figures for dynamic range:.

Typical outdoor sunlit scene.......100,000:1 Dynamic Range (DR).....~ 17EV Stops.

16Bit Tiff .............................. 65,536:1 DR ......................... ~ 16EV Stops.

The human eye ...................... 10,000:1 DR ....................... ~ 14EV Stops.

Average DSLR ......................... 400:1 DR ....................... ~ 8.5EV Stops.

Good Monitor ........................ 500 to 1000:1 DR ................... ~ 9 - 10EV Stops.

JPEG Image .......................... 256:1 DR ....................... 8EV Stops.

Photo Print .......................... 100 to 250:1 DR ..................... ~7 - 8 EV Stops.

Now after considering these DR figures I began to wonder about these multi-ink printers that are on the market. Usually, a colour printer has four inks (Cyan, Magenta, Blue and Black). But many of the higher end printers have from five to ten inks..

So am I right in thinking that the reason for the high number of inks in some printers is so as to increase the DR of the printer's output?.

If that is so, does anyone have an idea as to how many inks AND what colours it would take to get an inkjet printer's DR up to (1) the level of a good monitor and/or (2) up to the level of the human eye?.

Thanks in advance...

Comments (8)

Plevyadophy wrote:.

Now after considering these DR figures I began to wonder about thesemulti-ink printers that are on the market. Usually, a colour printerhas four inks (Cyan, Magenta, Blue and Black). But many of the higherend printers have from five to ten inks..

So am I right in thinking that the reason for the high number of inksin some printers is so as to increase the DR of the printer's output?.

No, it's more about color gamut..

If that is so, does anyone have an idea as to how many inks AND whatcolours it would take to get an inkjet printer's DR up to (1) thelevel of a good monitor and/or (2) up to the level of the human eye?.

A monitor is a light source, a print is light reflected off the ink and paper, you're not likely to ever see the two meet..

Paulhttp://PaulDRobertson.imagekind.com..

Comment #1

The list is accurate but misleading. The key is to understand the context in which they are using the term dynamic range..

Typical outdoor sunlit scene.......100,000:1 Dynamic Range (DR).....~17EV Stops.

Here they mean the actual light values..

16Bit Tiff .............................. 65,536:1 DR......................... ~ 16EV Stops.

Here they are making the assumption that the image is recorded linearly on a 1:1 scale. You could get far more than 16 stop of DR with 16 bits if you recorded on a different scale or recorded the values non-linearly. So technically, the value they give is incorrect..

The human eye ...................... 10,000:1 DR....................... ~ 14EV Stops.

I'm pretty sure the eye/brain records and/or processes light non-linearly. That's probably why it can see this large range..

Average DSLR ......................... 400:1 DR....................... ~ 8.5EV Stops.

I'd say you can add about a stop if you count highlight recovery..

Good Monitor ........................ 500 to 1000:1 DR................... ~ 9 - 10EV Stops.

I'm not sure what they mean exactly. And I think many specifications fudge toward higher numbers..

JPEG Image .......................... 256:1 DR....................... 8EV Stops.

Simply not true for the same reasons as with the TIFF image. You can easily record far more than 8 stops by recording non-linearly. Digital cameras do this all the time..

Photo Print .......................... 100 to 250:1 DR..................... ~7 - 8 EV Stops.

This refers to the print's reflectance range. But as with the TIFF and JPEG, it too can record a much broader range if the values are recorded non-linearly. In other words, you can "translate" a higher dynamic range scene so that it fits into a print with less DR..

Now after considering these DR figures I began to wonder about thesemulti-ink printers that are on the market. Usually, a colour printerhas four inks (Cyan, Magenta, Blue and Black). But many of the higherend printers have from five to ten inks..

No. Cyan, Magenta, Yellow and Black..

So am I right in thinking that the reason for the high number of inksin some printers is so as to increase the DR of the printer's output?.

Nope. They give a greater range of colors (gamut) that can be printed..

If that is so, does anyone have an idea as to how many inks AND whatcolours it would take to get an inkjet printer's DR up to (1) thelevel of a good monitor and/or (2) up to the level of the human eye?.

The print DR is a function of how black you can make the black portions and how reflective you can make the white portions. It isn't going to change much since the print relies on reflected light..

One of the key skills in making a nice photograph is the ability take the DR of a scene and judiciously adjust it's tones so that looks good in a print that has less DR. Simply fitting the DR is easy. But doing it so that the image looks good can be much harder and more time consuming. However, with today's digital tools, it is much easier than it was years ago..

Jay Turbervillehttp://www.jayandwanda.com..

Comment #2

Jay Turberville wrote:.

The list is accurate but misleading. The key is to understand thecontext in which they are using the term dynamic range..

Typical outdoor sunlit scene.......100,000:1 Dynamic Range (DR).....~17EV Stops.

Here they mean the actual light values..

16Bit Tiff .............................. 65,536:1 DR......................... ~ 16EV Stops.

Here they are making the assumption that the image is recordedlinearly on a 1:1 scale. You could get far more than 16 stop of DRwith 16 bits if you recorded on a different scale or recorded thevalues non-linearly. So technically, the value they give isincorrect..

The human eye ...................... 10,000:1 DR....................... ~ 14EV Stops.

I'm pretty sure the eye/brain records and/or processes lightnon-linearly. That's probably why it can see this large range..

Average DSLR ......................... 400:1 DR....................... ~ 8.5EV Stops.

I'd say you can add about a stop if you count highlight recovery..

Good Monitor ........................ 500 to 1000:1 DR................... ~ 9 - 10EV Stops.

I'm not sure what they mean exactly. And I think many specificationsfudge toward higher numbers..

JPEG Image .......................... 256:1 DR....................... 8EV Stops.

Simply not true for the same reasons as with the TIFF image. You caneasily record far more than 8 stops by recording non-linearly.Digital cameras do this all the time..

Photo Print .......................... 100 to 250:1 DR..................... ~7 - 8 EV Stops.

This refers to the print's reflectance range. But as with the TIFFand JPEG, it too can record a much broader range if the values arerecorded non-linearly. In other words, you can "translate" a higherdynamic range scene so that it fits into a print with less DR..

Now after considering these DR figures I began to wonder about thesemulti-ink printers that are on the market. Usually, a colour printerhas four inks (Cyan, Magenta, Blue and Black). But many of the higherend printers have from five to ten inks..

No. Cyan, Magenta, Yellow and Black..

So am I right in thinking that the reason for the high number of inksin some printers is so as to increase the DR of the printer's output?.

Nope. They give a greater range of colors (gamut) that can be printed..

If that is so, does anyone have an idea as to how many inks AND whatcolours it would take to get an inkjet printer's DR up to (1) thelevel of a good monitor and/or (2) up to the level of the human eye?.

The print DR is a function of how black you can make the blackportions and how reflective you can make the white portions. Itisn't going to change much since the print relies on reflected light..

One of the key skills in making a nice photograph is the ability takethe DR of a scene and judiciously adjust it's tones so that looks goodin a print that has less DR. Simply fitting the DR is easy. Butdoing it so that the image looks good can be much harder and moretime consuming. However, with today's digital tools, it is mucheasier than it was years ago..

Jay Turbervillehttp://www.jayandwanda.com.

Thanks very much for your detailed answer..

What do you mean by recording linear and non-linear?.

And reading your answers, and then considering the context in which the article I read was written (it was a magazine article about HDR), I think the article was really tallking about the different colours that each of those items above can record/relay (rather than light levels recorded/relayed)..

I note your answer about the number of inks that some of the higher end printers have. Do you by any chance have an idea as to how many inks as a MINIMUM are required to say reproduce a colour gamut that matches what the human eye can make out? And what would those colours be (for I notice some printers opt for extra blacks, whilst others go for different shades of red or blues etc)?.

Thanks in advance...

Comment #3

You may wish to consider using a photo printing service. They typically have better equipment than a hobbyist can justify. They also tend to have enough volume of business to allow lower prices than you will see doing the print yourself. For a really difficult print or a fine art print consider using a lab with custom services..

I find blue and violet difficult to hold in the color gamut of printers. If I have important areas of shades in that range I use a custom lab and speak directly with the person doing the color matching and printing..

Just a different viewpoint...

Comment #4

Thanks very much for your detailed answer..

No problem..

What do you mean by recording linear and non-linear?.

In a 1:1 linear system that starts at 255, a one stop difference halves the numeric values. So a one stop drop yields a value of 127. The next stop results in a value of half again, or 63. The numerical values track in lockstep with the light values. When light is halved, the numeric values are halved. Current raw files work this way, just not perfectly so.



Non-linear means that different tonal values get different numerical weightings. For instance, you might very well show four whole stops of tonal changes before you ever reach the 127 value. This is typically how raw software and in-camera processing treats the picture information. It allows you to record many more stops of DR in a smaller bit depth. From a pictoral standpoint, it is a much more efficient way to record image information..

And reading your answers, and then considering the context in whichthe article I read was written (it was a magazine article about HDR),I think the article was really tallking about the different coloursthat each of those items above can record/relay (rather than lightlevels recorded/relayed)..

The key is to keep in mind what is meant and not to confuse one with the other..

I note your answer about the number of inks that some of the higherend printers have. Do you by any chance have an idea as to how manyinks as a MINIMUM are required to say reproduce a colour gamut thatmatches what the human eye can make out?.

No. I really don't know. With pigments, I suspect it is simply not possible..

Jay Turbervillehttp://www.jayandwanda.com..

Comment #5

Jay Turberville wrote:.

I'm pretty sure the eye/brain records and/or processes lightnon-linearly. That's probably why it can see this large range..

The human eye can see in different ranges, eg from very dim to a certain level of brightness, or from some certain level of brightness up to very bright, but not all of both ranges at the same time. We all know about night vision and daylight vision and it's not just the size of our pupils, although that has a big effect. Monitor output is pretty much what it is, although perceived print output DR can arguably be increased slightly by varying the light intensity while you view (to open up shadows more vs seeing brighter detail), although that's not usually a practical thing to do..

Good Monitor ........................ 500 to 1000:1 DR................... ~ 9 - 10EV Stops.

I'm not sure what they mean exactly. And I think many specificationsfudge toward higher numbers..

Making monitors brighter extends DR in one direction, but that's not so useful for editing for printing as the monitor ends up being way too bright to be useful in judging how to process for the right print brightness (LCD monitors). In the other direction, you can get significant increases in DR specifications by providing blacker blacks, but I don't think they have much practical value for photo editing. An LCD monitor uses a backlight that gets blocked by the liquid crystals to create colours, including blacks. For a given backlight brightness, the more light the crystals block, the blacker the black. A contrast ratio of 'only' 400:1 or 500:1 is enough for accurate editing..

Photo Print .......................... 100 to 250:1 DR..................... ~7 - 8 EV Stops.

This refers to the print's reflectance range. But as with the TIFFand JPEG, it too can record a much broader range if the values arerecorded non-linearly. In other words, you can "translate" a higherdynamic range scene so that it fits into a print with less DR..

Exactly..

So am I right in thinking that the reason for the high number of inksin some printers is so as to increase the DR of the printer's output?.

Nope. They give a greater range of colors (gamut) that can be printed..

Not just gamut, but also the number of colours within the gamut to provide for smoother colour gradations. For example, the addition of a couple of shades of grey ink in addition to black ink makes for smoother B&W prints, and the same situation applies with colours. In addition to C, M and Y, better inkjet printers include at least lighter versions of C, M and Y that may be called light or photo C, M and Y..

If that is so, does anyone have an idea as to how many inks AND whatcolours it would take to get an inkjet printer's DR up to (1) thelevel of a good monitor and/or (2) up to the level of the human eye?.

The print DR is a function of how black you can make the blackportions and how reflective you can make the white portions. Itisn't going to change much since the print relies on reflected light..

Yes, but it's also the gamut. Current printing technology can't cover what the human eye can see. Current monitor technology can't do it either..

One of the key skills in making a nice photograph is the ability takethe DR of a scene and judiciously adjust it's tones so that looks goodin a print that has less DR. Simply fitting the DR is easy. Butdoing it so that the image looks good can be much harder and moretime consuming. However, with today's digital tools, it is mucheasier than it was years ago..

Good points. When we view a scene or image, we perceive how it looks, so when we print we want the print to look a certain way. I recently asked in one of my local print labs about the image quality of their high end Epson pro inkjet printer outputs on good paper vs their cheaper photographic print process. They said the biggest difference is that the inkjet output provides much better blacks, ie they are blacker and you can see more dark detail down to that black level..

To address the OP's question about print DR, printing is always a compromise. However, as a minimum, a printer with C, M, Y, Lt C, Lt M, Lt Y, black (K) and at least one lighter black is a starting point for good quality images. Keep in mind that the ink and paper being used makes a big difference, both inititally and over time as the print fades..

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #6

I'm pretty sure the eye/brain records and/or processes lightnon-linearly. That's probably why it can see this large range..

The human eye can see in different ranges, eg from very dim to acertain level of brightness, or from some certain level of brightnessup to very bright, but not all of both ranges at the same time. Weall know about night vision and daylight vision and it's not just thesize of our pupils, although that has a big effect..

Right. And if you don't blink or move your eye a bit, the the eye's sensitivity changes as whatever photochemical process the eye uses runs into depletion in certain areas. Sometimes while in the field waiting on birds, I'll find myself staring vacantly while I listen. I tend not to blink or move my eyes, and a strange visual effect occurs and my general field of visions turns grayish. I suspect this is an artifact of a pattern of depletion that matches the image formed on the retina..

An LCD monitor uses a backlight that gets blocked by theliquid crystals to create colours, including blacks. For a givenbacklight brightness, the more light the crystals block, the blackerthe black. A contrast ratio of 'only' 400:1 or 500:1 is enough foraccurate editing..

And then I guess the black point depends on the conditions that the monitor is viewed in. A dark room would yield a greater DR than a bright one..

One of the key skills in making a nice photograph is the ability takethe DR of a scene and judiciously adjust it's tones so that looks goodin a print that has less DR. Simply fitting the DR is easy. Butdoing it so that the image looks good can be much harder and moretime consuming. However, with today's digital tools, it is mucheasier than it was years ago..

Good points. When we view a scene or image, we perceive how itlooks, so when we print we want the print to look a certain way. Irecently asked in one of my local print labs about the image qualityof their high end Epson pro inkjet printer outputs on good paper vstheir cheaper photographic print process. They said the biggestdifference is that the inkjet output provides much better blacks, iethey are blacker and you can see more dark detail down to that blacklevel..

The same reason I used to use selenium toner on my black and white prints. If done moderately, it made the dark blacks go slightly darker and added a bit of "snap" to the image. It was also the reason many folks cursed resin coated papers. Though measurements often claimed that the blacks were as black, they never seemed so visually - to me and many others..

Jay Turbervillehttp://www.jayandwanda.com..

Comment #7

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #8

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