• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Archived

This topic is now archived and is closed to further replies.

Differences due to scan DPI?

Started by Fan4Fan,

21 posts in this topic

Fan4Fan

Fan4Fan

Posted
Posted

I recently got a book that does not look nearly as good as it did in the scan that was provided.

 

As an example, I scanned the top edge and juxtaposed the two (top is from the seller; bottom from me):

 

ScannedAndAsReceived_zps59c69279.png

It looks like the top was scanned at 96 DPI (or at least that is what the downloaded image is giving its properties at) and the bottom was at 300.

 

Are the differences:

 

- color loss/abrasion at the top of the Comics Code box and at various points along the upper edge

 

- discoloration

 

- tear with associated crease at center of the top edge

 

explainable by a lower DPI image?

 

Link to comment
Share on other sites
namisgr

namisgr

Posted
Posted
His scan looks sharper than yours.

 

Not when blown up 300%

 

Untitled-1-1_zps1689ab52.jpg

 

It would appear the top image has been modified in an image processing program - for example, on the top image the right edge has blurred cover where the bottom image has the splash page showing.

Link to comment
Share on other sites
rodan57

rodan57

Posted
Posted

I would say it looks like your book is damaged in different places. I might conclude that his scan is an older scan of the book.

 

I scan my books when I buy them. I suppose I would be tempted to use the same scan when selling -- even 5 or 10 years later to save on the effort of rescanning.

 

But I'd like to think that I would be sensitive to mishandling during that period of ownership and would rescan if I thought the book had been damaged or had browned.

Link to comment
Share on other sites
The Troll King

The Troll King

Posted
Posted
I recently got a book that does not look nearly as good as it did in the scan that was provided.

 

As an example, I scanned the top edge and juxtaposed the two (top is from the seller; bottom from me):

 

ScannedAndAsReceived_zps59c69279.png

It looks like the top was scanned at 96 DPI (or at least that is what the downloaded image is giving its properties at) and the bottom was at 300.

 

Are the differences:

 

- color loss/abrasion at the top of the Comics Code box and at various points along the upper edge

 

- discoloration

 

- tear with associated crease at center of the top edge

 

explainable by a lower DPI image?

 

The 96dpi is not a standard scanning level and was probably downsized by whichever hosting service he used.

 

If your scan is at 300dpi then we're not seeing it because there's no way that resolution from Blowies enlargement is 300. You posted it to photobucket which downgraded it also, and Blowie probably did as well which further degraded it from being enlarged.

 

Without comparing the source scans in real full resolution this entire thread is moot.

Do I think the seller doctored the image? No.

 

Link to comment
Share on other sites
Sal

Sal

Posted
Posted

Top image looks like it's got a moiré pattern from the lower resolution which is evening out the discolorations and damage that the bottom scan is showing

Link to comment
Share on other sites
dgarthwaite-migration

dgarthwaite-migration

Posted
Posted
His scan looks sharper than yours.

 

Not when blown up 300%

 

Untitled-1-1_zps1689ab52.jpg

That's JPG compression

 

I'd have to say I agree.

 

I save everything as uncompressed PNG now. The files are huge, but I can't stand JPG and the compression. JPG is technology from the 1990's. I'm baffled as to why the web hasn't pushed JPG and GIF to the wayside by now.

 

DG

Link to comment
Share on other sites
Fan4Fan

Fan4Fan

Posted
  • Author
Posted
Now I'm feeling even less like buying comics off of eBay if damage/discoloration can be evened out so well...

 

Defects can be completely removed with Photoshop. Sometimes in seconds.

 

DG

 

That's what I'm trying to figure out.

 

When I blow up the seller's image it seems like the top of the cover is very straight and clean (i.e. doesn't grade into shadow as it does elsewhere along the top) in some of the areas where defects are absent.

 

I don't have the time currently to go over the whole cover, so I picked the possible problem area where a tear seems to have disappeared.

Link to comment
Share on other sites
Davenport

Davenport

Posted
Posted
Now I'm feeling even less like buying comics off of eBay if damage/discoloration can be evened out so well...

Scans have to be done carefully, with a conscious effort toward matching reality as close as possible.

And, even more so, scans have to be viewed carefully, staying conscious of all the enhancing tweaks and adjustments available.

 

I still have a pic in my photobucket I put together years ago, mainly as a reminder. And, weirdly, they're both the exact same scan (look at the bottom glare-pattern). One incarnation used by Heritage, the other appeared in a later eBay listing.

 

ScanTweaks.jpg

Link to comment
Share on other sites
Dr. Balls

Dr. Balls

Posted
Posted

FWIW:

 

Scanners are not standard equipment with accurate settings out of the box - they have to be set to ensure that the scan is an accurate representation of the item being scanned. I would wager that nearly everyone using a scanner pays little attention to this.

 

From measuring your white point accurately, to matching the color space of your monitor, to hoping that the end-user's monitor is properly calibrated for soft-proofing images of things that aren't in front of them - it's an impossible situation that is a struggle for hobbyists, as well as people in my line of work.

 

Not to mention that using the 'standard', 'home' or 'simple' settings on a scanner might actually alter your scan to make it look "better" without you even knowing it's doing that. By running filters such as descreen, dust and scratches or other photo-corrective methods it will alter the appearance much like what the OP is showing. My guess is that the scanner descreened the image (as evidenced by the softened moire printing pattern) which has a way of softly blurring the final image.

 

it's a no-win situation and a constant struggle to match scan to color and color to monitor and monitor to printer - and has been since I plugged in my first scanner in 1995.

Link to comment
Share on other sites
Davenport

Davenport

Posted
Posted

Well said. (thumbs u

 

When selling comics for several years on eBay I used large scans to help communicate condition to potential buyers. And it was a real PITA to make sure a scan matched closely what I was seeing in-hand. Worth the effort though, never had a complaint.

 

But you're right, the casual user isn't going to do that, probably not even aware it needs doing. Or know how even if they wanted to.

 

It's the guys that do know how and use it to full advantage you got to be careful of. Almost impossible to call 'em on it.

Link to comment
Share on other sites
Go to topic listing