i) Capturing a full range of tones from the scanner or digital camera

PiezographyBW is capable of rendering 100% of the greyscale tones. It is therefore important that we capture the full range. When scanning a negative, we should attempt to set the highlight point at level 255 and shadow point at level 0. Most Photoshop users should already be familiar with "Histograms", and how to read them, so I'll not bother with it here.

The screen grab below shows an example histogram for a negative that I have managed to capture all the available information. Notice that neither the shadow nor highlights have been clipped, there is still room for manoeuvre. The histogram also shows that the bulk of the image data lies in the 3/4 tones (darker greys), although there is still plenty to work with in the lighter regions.

 

Maximising the range of captured tones

 

The user manual supplied with PiezographyBW explains the subject of optimising the range of tones for the image in considerable detail, so as before I won't repeat it here.

 

ii) Careful editing of the image

At first, this heading might appear to be a repeat of the previous section, but it isn't. This section differs; in so far as, it deals with calibrating the monitor and setting up Photoshop for PiezographyBW. I' now use Photoshop 6, so the screen grabs shown relate to that version of Photoshop. Nevertheless, the concept is similar for Photoshop 5 and of course, the PiezographyBW manual provides lots of help.

The dot gain of the PiezographyBW inks vary with the media used, so achieving an accurate preview of the print on the monitor is important. This must be done before we can even begin to consider editing an image. What follows may appear a tad complicated, but once completed you'll immediately realise the benefit. The process involves modifying (customising) the Photoshop "Dot Gain Curve".

First, we get Photoshop Color Setting setup correct for PiezographyBW. This is achieved by selecting the Photoshop Edit menu, followed by Color Settings. I discuss the configuration of this dialog in considerable detail in the article Colour Management and Adobe Photoshop 6, so I won't repeat it here.

The screen grab below shows the settings I use. Notice that "Gray" has a label Epson Photo Paper (PiezoBW). This label reminds me that the selected dot gain curve for greyscale images is set for the paper I normally use when printing PiezographyBW.

 

Photoshop 6 - Color Settings Dialog

 

The user manual also recommends that the "Color Management Policy" for greyscale images is OFF. This means that NO profile will be embedded in the image when it is saved. It also means that we can accurately preview our greyscale images using the custom dot gain curve.

We make our first print (which ideally includes the 21-step greyscale) and once finished compare it with the monitor image. Making sure the custom dot gain curve is open we now adjust the curve so that the image on screen appears like the print. Once satisfied we make another print. It may be necessary to go through this exercise a couple of times to refine the "dot gain" curve.

After a few trial prints that included the supplied "21-step greyscale" image, I arrived at the following dot gain curve for Epson Photo Paper. Other users will probably find different values, so don't take it as gospel!

 

Custom Dot Gain Curve for Epson Photo Paper

 

This curve has NO effect on the actual image data, only the preview and with it in place I am assured of a print that replicates the image as viewed on my monitor.

One of the comments that I often read regarding PiezographyBW is that it doesn't produce deep blacks. This is absolute nonsense! PiezographyBW will produce deep blacks with little effort, if that is what the user decides to print. However, the key to getting deep blacks is to have areas of true black within the image.

The Histogram I show above does NOT have pure blacks within it. No part of the image that it represented (see the Cathedral Interior screen grab, on page 1) is at Level 0. However, getting some of the image to be at Level 0 is relatively easy. The secret is to edit the shadows and leave he remainder of the image alone.

Again Jon Cone comes to the rescue, he has produced an excellent tutorial on the subject of editing our image files for better blacks. The tutorial can be fond at the following URL: - http://www.piezography.com/ts/shadows.html

Basically, the technique involves making a "Channel" mask as shown in the screen grab below.

 

Channel Masking for Selective Editing

 

Notice that the histogram only includes data in the shadow region of the image, all other data is masked and therefore protected from the edit. In the example shown (see the Info Palette) I pulled the shadow point towards the centre so that an area that originally had a value of RGB Level 31 became RGB Level 15 (K-88% became K-94% black). Even at K-94% black, this region will print with detail, but now the print will have a bit more depth to it.