THE REPRODUCTION OF BOTANICAL ART - Page 4

ABOVE : The blizzard plot shows the reds of the amaryllis on the previous page. They lie substantially outside the gamut of any matte art paper using Epson K3 UltraChrome ink.

ABOVE : The reds of the amaryllis set on our normal Lab plot of the Macbeth Color Checker. The red diamonds show the distance between the primary red of the Macbeth Chart and the pigment used by artist, Linda McCann. The inner diamond is the position of the red after conversion to an Epson Velvet Fine Art profile.

In order to explore the gamut employed by nature, we selected some bright flowers from the garden, measured them with the spectrophotometer and then scanned them. This is the final piece of the jigsaw – the petals are too far out of gamut for even the pigments of the artists to cope with. In the plot above, the colours of the petals are plotted on top of the gamut of an art paper. The order of things then is that the camera gets closest to the original, then the scanner, then paint, then inkjet onto art paper – everything is a compromise. We asked former Nature and Environmental Photographer of the Year, Andrew Williams, to contribute his thoughts on the matter and these are shown later in the feature. Interestingly his image of the flamboyant Helenium ‘Rubinzwerg’ is about 80% out of gamut for a printing press.

Masking

For a task such as this watercolour, the masking tactics are critical to the success and speed of execution. In reality there are few time constraints; we are not, after all, faced with masking dozens or even hundreds of images. There are so many ways of proceeding that we could devote the whole magazine to the topic (and more), but if you require more information you need look no further than Katrin Eismann’s book Photoshop Masking and Compositing (available from the SWPP bookstore at www.swpp.biz).

It is important, tactically, to save selections so that if any tweaking is required at the proofing stage this can be selective to the area in question. We started with the Magic Wand on a tight tolerance (typically 5–10) using the ‘add to selection’ mode to build up the selection of the background cream. When this eventually ran out of steam we switched to the Quick Mask and painted the edges where needed. This was done with a hard edged brush (at the start we seek a sharp mask). The problem of using the Magic Wand was that it could not differentiate between the paper base and the very light wash of grey, used to create the folds of the petals – the selection leaked into the body of the petals.

When the complete outline of the subject had been made it was saved as an Alpha Channel for reference. With the outline selected, it was then inverted (Ctrl-Shift-I) and a Levels Adjustment Layer created. For a subject such as this it is usually only necessary to bring the highlight slider down to about 245 RGB points to eliminate the background by pushing it to 255 RGB points – not technically erasing, simply driving it out beyond the clipping point. This left a residual dot pattern of around 245 RGB points on those parts of the petals that were at paper-cream in the original. Once we were satisfied with the outer surroundings to the plant, the mask attached to the adjustment layer was activated (focused) and softened using Gaussian Blur to between 2 and 6 pixels (for a typical 30 to 40Mb scan).

Control of the other colours within an image may need selective masking. If, for example, the proof shows the leaves to be a little under-saturated or slightly off hue, a Hue and Saturation adjustment layer might usefully be employed. It might pay dividends to add to the layer mask from the outline to prevent any changes influencing the outer margins of the image.

If, as was the case with our scans, there are benefits from applying a profile to correct the leaves but not the highlights, making a duplicate image and combining the two approaches can work well. In doing this you have to obey the colour management rules. If you have assigned a scanner profile to an image and you wish to paste in the duplicate with a different profile then you need to change the scanner profile version to say Adobe RGB and bring your ARGB duplicate in. With ‘warn when pasting’ checked in your ‘color preferences’, you will get a warning if you make a mistake. When confronted with the pasting choice to ‘preserve color appearance’ or ‘preserve color numbers’, you usually preserve appearance.

We left the signature on our master file. If the artist is to individually sign a limited edition, this would have to be removed after scanning.

The mask is first made with a hard edge. Note the Magic Wand has sought out the paint undulating in and out of the hills and valleys of the original textured paper surface.

The mask is loaded as a selection, then a Layer Mask is made which is softened with Gaussian Blur.

The mask leaves a hard jagged edge where paint meets paper. In the bottom image the softened mask is blending the image in but leaving a tell-tale slightly strong grey edge line. This is 'choked' using Levels on the Layer Mask as shown below to the right.

Photo Quote: You've got to push yourself harder. You've got to start looking for pictures nobody else could take. You've got to take the tools you have and probe deeper. - William Albert Allard