Previuos Page     Page 4 of 4     Next Page

The finishing touches!

Everyone has their own views as to what needs to be done to an image before it's exported into Photoshop. The following are few hints as to which tools offer the quickest and easiest route to a reasonably colour/tone accurate image. Obviously you should experiment by yourself, it's only through such trial and error that you can ever hope to learn SilverFast.

Before I discuss some of the tools we have one more dialog to configure, the Auto settings dialog. You can access this dialog by simply pressing the Option button followed by selecting the Auto tab. The following screenshot shows "my" settings. They are, excepting two the default settings.




The Colour Cast Removal tool is a new feature introduced in version 5.2, and comes in handy with some images. When set for 100% any colour cast (as determined by SilverFast) will be totally removed. Sometimes this a good thing, on others it makes for a horrible effect, pick your values wisely, but something in the order of 10% to 20% might be enough for most images. You won't see the effect immediately or might never see any at all, so don't expect any on screen change to your image yet.

Next,  I deselect the Auto Contrast, I have no liking for this feature, but you may feel differently. You can refer to the SilverFast manual for a more comprehensive explanation of each of the remaining settings.

The Tools in use

The tool bar running across the top of the Frame dialog is the real powerhouse of SilverFast. I'll only be touching on a few adjustment tools, but at least should get some idea of where to start.



SilverFast Adjustment Tools Palette


Automatic Tone and Colour Correction

We can identify whether SilverFast will or will not automatically apply colour correction by checking which form the Auto Adjustment (aperture symbol) takes in the Adjustments toolbar - and both mean that Auto Colour Correction will NOT take place and means that it will.

So our first step in colour/tone correcting the image is to press the Auto Adjust button. Users with IT8 calibration or a customised ICC scanner profile will find that SilverFast ignores any colour casts it finds in the pre-scan and so Auto Adjust will simply correct the tonal range of the image. Usually the shadows will darken and the highlights brighten. With some images the midtones can also change. We can see what has changed without even inspecting the image because either the histogram  b2 and/or gradation button will have changed colour (e.g. b3).

If on the other hand you are using SilverFast without the benefit of IT-8 calibration or a custom ICC profile then SilverFast will automatically remove any colour casts found in the image (not a good idea for sunsets). The user can preset the amount of automatic colour cast removal by inserting a value into the Color Cast Removal popup shown in the Histogram dialog below.  The default value of 100% will completely remove the colour cast an a value of 0% will leave the cast untouched. Alternatively we can hold down the Shift key when pressing Auto Adjust B1  and the colour cast will be retained. 

Remember the Colour Cast Removal option mentioned above, well now you should appreciate why I suggested values between 10% and 20% as starting points. If we look at the Histograms below it can be seen that in one the system has cancelled out only 20% of the colour cast. Had I set a higher or lower value then the Histogram would reflect that. Also note that you can fine tune the degree of cast removal by dragging the slider left or right. The second Histogram shows the effect of leaving the default value of 100% colour correction.


Image Image
Auto Colour Correction at 20% Auto Colour Correction at 100%


The black points and white point have also been set automatically as per the values we chose in the Auto dialog above.

Next we look at the Gradation Curves dialog for the same image as was used for Histogram correction. The first screenshot shows that only the gradation (or gamma) has been modified by the automatic settings and the second shows the effect of leaving Auto Contrast ON. As with all SilverFast adjustment tools we can make further adjustments as needed.


Image Image
Auto Contrast OFF Auto Contrast ON


As with Photoshop we can pull the master or individual colour channel curves in any way we choose thus optimising contrast, etc. We can achieve this by simply moving the gradation slider or just grab the curve and pull it. The brightness and contrast of the image can be further refined, as can the highlight and shadow points. Remember all of this is occurring on a high-bit image, so the amount of image data being trashed is minimal. Better still, the original scan will never be changed, it remains intact.

Manual Tone and Colour Correction

The above method was based upon automatic correction of the image with some manual fine-tuning. For those who prefer manual correction SilverFast Ai and HDR have the tools. I mentioned the highlight and shadow points above and how they were automatically adjusted, but say you didn't want them adjusted automatically, or worse didn't know were they where. Not a problem, finding the white or black point in an image is a simple matter of clicking with the white or black square on the  b4 tool. Once you find the required points in the image then simply click them with either the highlight  b5 or shadow tool, and the image highlight or shadow will be brought to neutral. The centre of this icon can be used to set midtones to neutral. Again the gradation curves dialog has a major part to play in getting colour and tone correct, so experiment.

The remaining icons on the toolbar, i.e. Global Colour correction b6 Selective Colour correction are discussed in Tutorial 3 and well worth investigating all the same. Further guidance on basic image editing in SilverFast can be found HERE

Once you are satisfied with the corrections it simply a matter of transferring the corrected image to Photoshop for printing, saving whatever. This is achieved quite simply by pressing the Scan RGB button.




Whiterocks and Cloud Pattern - North Antrim Coast



Previuos page     Page 4 of 4     Next Page
Contents on this site: Ian Lyons 1999 - 2017. All Rights Reserved