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Welcome to Dijemeric Visualizations

Where photography and mathematics intersect with some photography, some math, some math of photography, and an occasional tutorial.

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Friday, January 18, 2013

Creating a Flickr Slide Show on Your Blog

Creating a Flickr Slide Show
(c) Ken Osborn 2013

Yes, you can post a Flickr slideshow on your blog site using a gadget, but what if you want a little more control?  For that I'm trying the slideshow generator called Flickr Slideshow Generator!  You can find it at

You can make a slide show based on tags, like this one from my sets tagged 'Dickens.'

 To start the process you will need an NSID which is a unique number representing you on Flickr.
Entering Information to Access Flickr Images

 To find your id number use idGettr at
idGettr will Get Your Unique Flickr ID Number

After you get your ID you then enter either a set URL with or without tags or just tags.  If you enter just tags it will grab everything in your Flickr stream with the tag so don't get too crazy because if you are like me you may have a lot of images under some particular tag.  

Generating the Flickr Slideshow creates an HTML code you can cut and paste into your blog website.
HTML Code for Website

Sunday, January 13, 2013

Do You Really Need a Zoom Lens?

Do You Really Need a Zoom Lens
Ken Osborn (c) 2013

If you have a camera that can take a 25 MP (mega-pixel) image, you may have asked yourself "why do I need a zoom lens?"  If, like me, you aren't printing posters and mainly show your photos on your website, why not just use a good prime 50 mm lens?  Maybe a 70 mm if you are doing portraiture.   With a zoom you can compose the way you want in the field, but if you are going to resize the image prior to posting, what is the difference between doing that and cropping from a larger image?  After all, you have all those extra pixels does it really matter how you waste them: by reducing resolution or by cropping them away?

I decided the only way to answer that question was to try it.  

I used an 18-55 mm zoom lens on a Pentax K5IIS to take two photos.  The first at a zoom of 18 mm and the second at 55 mm.  

Image 1: 18 mm zoom
Image 2: 55 mm zoom
The 18 mm image was cropped to the focusing chart for an image size of 423 pixels wide.  The 55 mm image was cropped to the focusing chart and then resized to 423 pixels wide.  So now both images have the same target filling the view and are both at the same final resolution.  The results are immediately below with the 55 mm zoom photo on the left and the 18 mm photo on the right.  (Click on the image for a larger view.)

Comparing Resizing (left) vs Cropping (right)
I have concluded I will keep my telephoto!

Saturday, January 05, 2013

Restoring Old Comics and Memories

Restoring Old Comics and Memories
Ken Osborn © 2012

If you know Photoshop, like old comics, and would like to see what they looked like new, read on.   

I was and still am a big fan of Carl Barks duck stories: Donald Duck; his nephews Huey, Dewey, and Louie; Uncle Scrooge and a host of relatives.  Trying to refresh my memory on a Scrooge adventure I found an incredible resource, the Duck Comics Revue by Geoff Moses at 

Geoff’s blog is filled with all sorts of goodies including panels from some well remembered stories.  But after a few decades the print had faded.  Those old dime comics were printed on a cheaper paper and were not intended to last forever. 

But with Photoshop it’s possible to restore these faded memories to their former glory.   Below are an original scan of a comic panel from the Duck Comics Revue followed by the restored version.

Faded Original
Restored Contrast and Colors
Starting with the scan, open it in Photoshop and take a look at the histogram. 

Histogram Using Photoshop Levels

The histogram is not evenly spread across the full width with a space at the right (highlights) end consistent with the yellow faded appearance.  Mouse click the ‘Auto’ button to improve the contrast. 
Auto Adjust Levels

Notice that the histogram is now spread across the full width and the contrast has improved. But there is still a yellow cast.  To remove the yellow cast select the white ‘eye dropper’ (it’s the one on the right) and then use it to select an area of the panel border that is yellow but originally white.
Eye Dropper for Bright Whites

Maybe too white
This is probably a bit harsh and the original was probably somewhere between bright white and faded yellow, so fade the levels about 50%.

Levels Faded 50%

Scanning the comic book will usually leave the print just a little soft, so a bit of sharpening may make the content a little more readable but it’s easy to overdo it so you may need to fade the sharpening.

 Sharpening a Little Harsh with Halos

Sharpening Faded

Before leaving the topic, here is one more example from a classic Donald Duck adventure, Trick or Treat (1952).

Original from Trick or Treat
Restored Version

And that’s it.  If you want to see a restored version of a 1950’s 3D Donald Duck giveaway, check it out at on Geoff Moses’ blog.