PIEZOGRAPHY BW - MONITOR CALIBRATION ISSUES
Please report errors or omissions to Bill Bergh - bill@cone-editions.com

The Piezography BW manual details a procedure for calibrating the monitor for greyscale, and when set up correctly the prints will match very closely to the monitor.  In other words, if you can trust what you see on the screen then you will know how to intelligently edit the image to achieve your artistic goals.

Calibrating the monitor can be a bit confusing at first, and we receive a lot of calls for generic advice.  There are a couple of settings in Photoshop that can cause problems, that are easily explained.

For the following information below, it is assumed that you have already set up the Photoshop default color management policies, as detailed in another document or link entitled "Correctly Printing the 21 Step Test Strip".  These settings must be correct to keep from distorting the image data prior to calibrating the monitor.  If you have NOT set up the default Photoshop color management policies, do so before proceeding.

MONITOR CALIBRATION ISSUES:
 1 - DOES THE GREYSCALE MONITOR CALIBRATION USE ICC PROFILES?
 2 - WILL THE GREYSCALE CALIBRATION EFFECT MY COLOR CALIBRATION?
 3 - WHY NOT USE THE ICC WORKFLOW?
 4 - HOW ACCURATE IS THE PREVIEW?
 5 - DO I HAVE TO BUY A MONITOR CALIBRATOR?
 6 - WHAT IS THE BEST IMAGE TO USE FOR CALIBRATING THE MONITOR?
 7 - DOES THE CALIBRATION PROCEDURE CHANGE THE IMAGE DATA?
 8 - IN PHOTOSHOP 5.x, WHEN I MOVE THE DOT GAIN CURVE, NOTHING CHANGES.
     (setting the Photoshop greyscale defaults)
 9 - IN PHOTOSHOP 6.x, 7.x, WHEN I MOVE THE DOT GAIN CURVE, NOTHING CHANGES.
     (setting the Photoshop greyscale defaults)
10 - DO I NEED TO SAVE A DIFFERENT CURVE FOR EVERY PAPER?
11 - IN PHOTOSHOP 5.x, HOW CAN I SAVE A DIFFERENT CURVE FOR EVERY PAPER?
12 - IN PHOTOSHOP 6.x, 7.x, HOW CAN I SAVE A DIFFERENT CURVE FOR EVERY PAPER?

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SOLUTIONS:

1 - DOES THE GREYSCALE MONITOR CALIBRATION USE ICC PROFILES?
No.  Photoshop 4 included a great CMYK onscreen preview (called a soft proof).  This was primarily used by printers with CMYK printers such as the Iris printer.  Photoshop 5.x added ICC workflow, but the only image preview that was available was for CMYK.  Photoshop 6 finally added softproofing preview capability for RGB files.

The ICC workflow automates the preview function.  Small patches of color (our ICC profiles measure 750 patches) are measured using expensive photospectrometers, and a numeric table is created that defines the color as measured and the CIE Lab equivalent.  This numeric table is called an ICC profile.  Photoshop and other ICC aware applications can use this set of numbers to accurately display onscreen the colors as they will be printed, assuming that the monitor has also been measured and profiled.

Before there was anything called an ICC workflow, people still managed to print successfully.  In Photoshop 4, you could manually define a custom set of numbers for CMYK printing that would be used for the onscreen preview.  This manually defined preview was used by professional printmakers.  They used the setup screens to define custom dot gains for their inksets after printing a number of test strips.

Greyscale work is considered a subset, or smaller part, of CMYK.  Photoshop can be set up so that greyscale work uses the black ink only channel.  We are using this older method for very specific reasons.  First, better control of the preview.  Second, this method does not interfere with the color setup as discussed below in item 2.  This method was a lot of work and a pain when dealing with 4 channels of ink in CMYK.  But  when dealing with values of grey, we are looking at the "Value", not the "Hue" of the channel, and this method is quite simple.

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 2 - WILL THE GREYSCALE CALIBRATION EFFECT MY COLOR CALIBRATION?
No.  As discussed above in item 1, we are using the manual dot gain preview setup for the black channel of CMYK printing.  One of the advantages of this method is that the color calibration and the greyscale calibration are kept separate.  We can use this to good advantage.

Once you have the greyscale setup as detailed in the PiezographyBW manual, you can open up an RGB color document and Photoshop will use the normal ICC workflow.  When you open a greyscale image, Photoshop will use the manual custom dot gain that you have set up.

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3 - WHY NOT USE THE ICC WORKFLOW?
RGB profiles have no black channel.  Black is the absence of the three primarily colors.  Equal mixtures of RGB from 0,0,0 (black) to 255,255,255 (white) represent the different possible grey levels.  To adjust an ICC profile, you would need to have ICC profile editing software, which can be quite expensive.

To really finesse the onscreen preview of your image - we prefer the custom dot gain of the K channel of CMYK.  One of the things that you will probably notice when first printing the 21 step test strip on the PiezographyBW CD disk, is that on the monitor, the 95% and the 100% step squares are all black.  On the printed paper - the difference is easily discernible.  Because CMYK has a black channel, using the curve function of the custom dot gain settings, we can tweak the preview to our hearts content.  If you spend 5 to 10 minutes, you can achieve a good onscreen match to the printed piece, and there is no extra software to buy.

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4 - HOW ACCURATE IS THE PREVIEW?
The onscreen preview can be quite accurate.  We found a curious limitation of the monitors, while we creating a test image.  The test image had concentric boxes and circles and step strips that zeroed in on the extremes of the printable ranges, the very lightest greys  from 1% to 5% black, and the deepest shadows from 95% to 100% black.  While we could see differences on the printed paper, we could not see the differences on the monitor when we filled the areas with a value.  We had to  adjust the monitor full bright to see the differences between 97, 98, 98% black etc., and conversely darken the monitor to see the extreme highlights to be able to see the differences between 1, 2, 3% black etc.

In actual practice, a person does not typically edit the last 5% on either end, and this is one case where the additional detail on the printed sheet is a pleasant surprise.  Actually - there is no other driver that can print differences in these regions.

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5 - DO I HAVE TO BUY A MONITOR CALIBRATOR?
For color work, this is a must.  There is no way to accurately use the ICC workflow without actually measuring your specific monitor and creating an ICC profile from the measured values.  For greyscale work, this is a harder question to answer.  As long as the monitor is not seriously misadjusted,  you will probably do just fine.  Even if there was a slight cast to the monitor, the B/W photographer has a trained eye for looking at value, disregarding hue.  In many ways, calibrating a monitor for greyscale is much simpler than calibrating for good color matching.

If you also print color work, seriously consider buying monitor calibration software and hardware.  There is no substitute.

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6 - WHAT IS THE BEST IMAGE TO USE FOR CALIBRATING THE MONITOR?
We have provided a 21 step test strip on the PiezographyBW CD disk for this purpose, or you can make your own 21 step strip in Photoshop.  It is recommended that you use this as a starting point rather than an image of a tree etc., that may not have easily discernable gradations that cover the full tonal range of the inkset.  A fresh copy of the 21 step strip can always be downloaded from :

http://www.inkjetmall.com/store/cone_ts/piezobw_update/

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7 - DOES THE CALIBRATION PROCEDURE CHANGE THE IMAGE DATA?
No.  We are tweaking the onscreen preview of the data using the manual dot gain preview adjustment features of Photoshop.  This has been available in Adobe Photoshop since at least Photoshop 4.  In other words, we print a target and by moving the dot gain curve adjustments, we are visually telling Photoshop how to best display the image so that the monitor best matches the printed output.

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8 - IN PHOTOSHOP 5.x WHEN I MOVE THE DOT GAIN CURVE, NOTHING CHANGES.
This problem is easily fixed, and means that one of your settings was incorrect.  Go through the following list, and ensure your settings match.  The procedure is the same for Mac or Windows operating systems.

PROCEDURE:
8.1 - Open an a greyscale image in Photoshop 5.x, preferably the 21 step test strip from the Piezography CD disk.

8.2 - While in Photoshop 5.x, click on "File" -> "Color Settings" -> "Greyscale Setup".

8.3 - In the Greyscale Setup box, make sure that "Greyscale Behavior" radio button is set to "Black Ink", and that the "Preview" box is checked.

8.4 - Click the "OK" button to close the Greyscale Setup box.

8.5 - Next click on "File" -> "Color Settings" -> "CMYK Setup".

8.6 - In the CMYK Setup box, make sure that "CMYK Model" radio button is set to "Built In" and that the "Preview" box is checked.

8.7 - In the CMYK Setup box, click on the "Dot Gain" drop down list and select "Curves", which will open up the "Dot Gain Curves" box.

8.8 - In the "Dot Gain Curves" box, make sure to select the "Black" radio button or the check box for "All Same" in the lower right corner.  The DEFAULT is CYAN ink, and this is the leading cause of problems.  If you select (by default) the Cyan channel, then nothing will change when you have open a greyscale image (black channel) and move the dot gain curve around.  When you move the curve with "Black" or "All Same" selected, you will see the image on screen darken and lighten.  Similar to all curve adjustments in Photoshop, you can move the whole curve for overall changes, or pin down the curve with point selections and just adjust a narrow area.  A good place to start is the deep shadows.  You will probably see that on the monitor, the 95% and the 100% step squares are all black.  On the printed paper - the difference is easily discernible. Adjust the curve until the monitor displays the same value difference as the printed paper.  Continue from box to box until you have a good match for all boxes from monitor to printed paper.

8.9 - In the "Dot Gain Curves" box, select "OK" to exit.

8.10 - Back in the CMYK Setup box, notice there is the option (middle right) to "Load" and "Save" your settings.  This will be covered below under topic 10 and 11.  Select "OK" to exit.

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9 - IN PHOTOSHOP 6.x, 7.x, WHEN I MOVE THE DOT GAIN CURVE, NOTHING CHANGES.
This problem can be a bit more tricky than Photoshop 5.x.  It may happen because one of your settings was incorrect, or worse if the image was converted when opening.  Go through the following list, and ensure your settings match.  The procedure is the same for Mac or Windows operating systems.

PROCEDURE:
9.1 - Open an a greyscale image in Photoshop 6.x, 7.x, preferably the 21 step test strip from the Piezography CD disk.

9.2 - While in Photoshop 6.x, 7.x, click on "Edit" -> "Color Settings".

9.3 - In the "Color Settings" box, make sure that "Advanced Mode" check box is checked (upper left), and that the "Preview" box is checked (middle right).  The "Advanced Mode" check box is the number one cause of problems.

9.4 - In the "Color Settings" box, in the "Working Spaces" area, click on the "GREY" drop down menu and select "Custom Dot Gain" at the very TOP of the list.  which will open up the "Custom Dot Gain" box.  The Custom Dot Gain selection will not be available if the "Advanced Mode" check box is NOT checked in the preceding stop.  This is the second leading cause of problems.

9.5 - In the "Custom Dot Gain" box, when you move the curve, you will see the image on screen darken and lighten.  Similar to all curve adjustments in Photoshop, you can move the whole curve for overall changes, or pin down the curve with point selections and just adjust a narrow area.  A good place to start is the deep shadows.  You will probably see that on the monitor, the 95% and the 100% step squares are all black.  On the printed paper - the difference is easily discernible. Adjust the curve until the monitor displays the same value difference as the printed paper.  Continue from box to box until you have a good match for all boxes from monitor to printed paper.

At this point, if the image on screen is not changing while moving the curve - it means that the document was opened using an embedded profile, or worse yet, the image data was converted to the current working space.  It is preferable not to continue in this manner.  There is a way out of this, but in the case where the data was converted to the working space, the damage is done and it is best to close the document and re-open it.  You need to set up the Photoshop default color management policies, as detailed in another document or link entitled "Correctly Printing the 21 Step Test Strip".  Do this first before trying to adjust the monitor preview.

9.6 - In the "Dot Gain Curves" box, notice that you can change the name of the Custom dot gain curve.  This will be covered below under topic 10 and 11.  Select "OK" to exit.

9.7 - Back in the "Color Settings" box, notice there is the option (middle right) to "Load" and "Save" your settings.  This will be covered below under topic 10 and 11.  Select "OK" to exit.

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10 - DO I NEED TO SAVE A DIFFERENT CURVE FOR EVERY PAPER?
In general when you first start out, you will probably find that a custom dot gain setting for a water color paper works well for other types of water color paper etc..  Get some experience printing with PiezographyBW.  But as time goes by, your eye will become more discerning.  It will be time to go back and fine tune a the custom dot gain settings for a particular paper.  If you experiment with different papers, you will see that each is unique in how dark the pure black will appear, and how the over all range of values is slightly different.

If you feel that your monitor is accurate to the printed paper - then don't worry.  We get calls from people that feel somehow uneasy, and are concerned that they should be somehow doing something different and that it can't be so easy.  Take a deep breath and let go of your worries.

Many want to tweak everything to the last ounce of perfection, and have specific dot gain settings for every paper they print on.  Go for it.

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11 - IN PHOTOSHOP 5.x, HOW CAN I SAVE A DIFFERENT CURVE FOR EVERY PAPER?
Different curves settings for the dot gain preview can be saved and loaded in Photoshop 5.x.  The procedure is the same for Mac or Windows operating systems.  We recommend that you name the curve with a unique name of the paper, so that it makes sense later.  If you make more than one for the same paper - add a number to the name will help keep them straight.

PROCEDURE:
11.1 - Open an a greyscale image in Photoshop 5.x, preferably the 21 step test strip from the Piezography CD disk.

11.2 - Next click on "File" -> "Color Settings" -> "CMYK Setup".

11.3 - In the CMYK Setup box, click on the "Dot Gain" drop down list and select "Curves", which will open up the "Dot Gain Curves" box.

11.4 - In the "Dot Gain Curves" box, once you have adjusted the curve setting until you have a good match  from monitor to printed paper, select "OK" to exit.

11.5 - Back in the CMYK Setup box, click on the "Save" option (middle right) to save your settings. Makes sure to name the settings with an appropriate name that will make sense later.

11.6 - Select "OK" to exit.

11.7 - If you have created different curves for different papers,  there is the option (middle right) to "Load" the saved curves.  If you had a curved saved for Cone Tech Gloss, and another for Cone Tech Orwell, then you would load the gloss curve when you are printing on the gloss paper so that you can properly view how the image will print, and then load the curve for Orwell when switching to this paper, a lightly  textured water color type paper.

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12 - IN PHOTOSHOP 6.x, 7.x, HOW CAN I SAVE A DIFFERENT CURVE FOR EVERY PAPER?
Different curves settings for the dot gain preview can be saved and loaded in Photoshop 6.x, 7.x.  The procedure is the same for Mac or Windows operating systems.  We recommend that you name the curve with a unique name of the paper, so that it makes sense later.  If you make more than one for the same paper - add a number to the name will help keep them straight.

PROCEDURE:
12.1 - Open an a greyscale image in Photoshop 6.x, 7.x, preferably the 21 step test strip from the Piezography CD disk.

12.2 - While in Photoshop 6.x, 7.x, click on "Edit" -> "Color Settings".

12.3 - In the "Color Settings" box, in the "Working Spaces" area, click on the "GREY" drop down menu and select "Custom Dot Gain" at the very TOP of the list.  which will open up the "Custom Dot Gain" box.  The Custom Dot Gain selection will not be available if the "Advanced Mode" check box is NOT checked (upper left).  Notice that you can change the name of the Custom dot gain curve.  Once you have adjusted the curve setting until you have a good match from monitor to printed paper, change the name of the curve to an appropriate name that will make sense later.

12.4 - In the "Dot Gain Curves" box, select "OK" to exit. There is a real trap here.  When you have changed the name of the curve - it will show up in the "GREY" menu of the "Working Spaces" area, the "Color Settings" box - but you have not "saved" anything.  If you do not save your settings in the next step then the curve is lost.

12.5 - Back in the "Color Settings" box, notice there is the option (middle right) to "Load" and "Save" your settings.  When you click the "Save" button, a "Save" box will pop up that gives you the opportunity to name and save these settings.  We recommend that you use the name you chose above for the curve.  Makes sure to name the settings with an appropriate name that will make sense later.

12.6 - If you have created different curves for different papers,  there is the option (middle right) to "Load" the saved curves.  If you had a curved saved for Cone Tech Gloss, and another for Cone Tech Orwell, then you would load the gloss curve when you are printing on the gloss paper so that you can properly view how the image will print, and then load the curve for Orwell when switching to this paper, a lightly textured water color type paper.

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