The question that is often asked is 'Can I make measurements from images that are displayed on the Internet?'. The answer is yes, but the quality is generally too poor to enable one to make accurate determinations. For the scale displayed on the ruler to be correct, the scanned image must not have been resized. This is clearly illustrated in Fig. 10. For display purpose, I wanted an image width of 400 pixels. The original image size was 645 pixels. I clicked on Image, then clicked on Resize, then clicked on Image Size and then set the width to 400. The original image is displayed on the left and indicates the width of the stamp design measures about 22 mm. However, after the resizing of the image, the width of the stamp design now measures just over 13 mm. Clearly this image must be adjusted so that correct measurements can be determined.
From the original image, the correct width of the stamp design is 21.9 mm. After the resizing, the width of the stamp design is 13.5 mm. The width can only be increased by increasing the number of pixels. The factor that is required is 21.9/13.5. The new width then would be 400 X (21.9/13.5) or 649 pixels which is close to the correct value of 645 pixels.
Any image on the Internet can be captured by clicking on the image with the right cursor button, then clicking on Save Picture As.... and finally selecting the name and location of the to be saved image. An image I captured from an auction item on eBay is displayed in Fig. 11.
All the images have been reduced in size. The left image is that of the overprinted stamp being auctioned off. The width of the stamp design is measured as 50.2 mm. The center image is that of an image obtained at a resolution of 600 dpi and the correct width of the stamp design is 21.9 mm. Activate the Image Size display (click on Image, then click on Resize and then click on Image Size). The value of the Resolution was 200 dpi and the image width was 479 pixels. The pixel width will have to be changed to 479 x (21.9/50.2) or to a value of 209. On the Image Size display, type in 209 for the pixel width. Click on OK. Once again activate the Image Size display and double click within the resolution box and type in 600. Click on OK.The measurements will now be correct as can be determined by measurement of the width of the stamp design. That is displayed in the right image. The overprint was then cropped out and the background color converted to white. The extracted overprint is displayed in Fig. 12.
The measurements are 0/56 which - among others - could be a Form 1 position 93. The side by side comparisons are displayed in Fig. 13.
My opinion is that this is a forgery.