Scanned Photo File Format

[Jim Conley]

Hello all.

I am also new to this Forum and to Laser Engraving. I will get my Epilog Mini 24 next month. But, in the mean time I am trying to get familiar with CorelDraw. I have read the Epilog manual and gone through their mini courses, I found many references on file manipulation, but very little on the actual scanning process. I have a Epson V750 Pro Flatbed Scanner.

I am planning on scanning some 8x10 B&W photos for use in Scanning on brass, aluminum, and or wood. Some will be engraved at the 8x10 size and others smaller depending on the item I am describing.

I am looking for advise on:

1/ What size should I scan the photo?

2/ What file type should I save it as?

3/ Should I scan it as a RBG? 24 bit? B&W?

4/ What is the best file format to import photos from a digital camera? Size? Resolution?

Any and all help and suggestions are appreciated.

Thanks

Jim

[Martin Boekers]

Welcome aboard! There are a handful of us in the Metro area. I am at Scott AFB IL

Typically I scan to size color RGB 300dpi save as a TIF

Start a folder with orig scans and use a duplicate file to work with that
way you always have your orig untouched.

In Photo Shop or Photo Paint (Corel) you can do your black and white
conversions as you have more control of the image, there are many
ways to get there so do a search to find out what works the best.

Search the forum for Photo Engraving as there are many ways to
do it depending upon the laser and software you use.

Search here for the Gold Method and it will give you a conversion
from grey scale to a "half tone"

Photos aren't the easiest thing to do so figure on going through a bunch
of test on scrap.

Keep a notebook for reference settings in the future.

Each material will engrave with different settings keep that in mind.

The best you can get you image to look in grey scale the better it will turn out!

Good luck and be sure to post some images!


Marty

[Dan Hintz]

If you plan on color sublimation, stick with RGB... if you'll only be laser engraving, you can save a lot of space by going with 8-bit grayscale (space is cheap these days, though, so take that with a grain of salt). For single-use images, JPEG is perfectly fine if you select a sufficiently high quality factor (low compression factor)... say, 90% or better. If you intend to do some image manipulation and/or you think there will be changes in the future, save as a TIFF.

300dpi is fine for the final save/engrave, but I will usually scan at 600 dpi, especially if I know I will be manipulating the image, such as fades and silhouettes, to cut down on degradation.

Unless you have a camera that saves in RAW format, you'll most likely get JPGs... size your capture to the final product. If your picture will only end up on a 4x6 tile, a low- to medium-res image form the camera is fine. If it's on a 12x12 or larger, I would highly suggest high-res. I use an 18MP camera and everything is shot at high-res... I'd rather have too much than too little when it comes time to start modifying the image.

[Doug Griffith]

Also remember to save your working file to a lossless format such as a PSD or non-compressed TIFF. Otherwise, each time you save the file and reopen it, artifacts from the lossy compression will be increase rapidly.

[Mike Null]

Jim,
Welcome to SMC. I live in Ballwin also--we may be neighbors. Feel free to give me a call.

[Dan Hintz]

Otherwise, each time you save the file and reopen it, artifacts from the lossy compression will be increase rapidly.
Maybe... it depends. Are you compressing for file size or quality? If by file size, then yes, any change you make that goes above the size limit can create more error (though unless the changes are radical, the changes will quickly stabilize and error deltas will fast approach zero (i.e., no more degradation). Errors will be across the entire image as a whole, but the most significant errors will be in the high-frequency areas first.

If by quality, then errors can build up in areas that have been modified (the blocks), but only those areas... everywhere else will already have had their values quantized to the quality level you choose, so no changes will be made to them. If you change quality level to be less, then yes, you'll degrade, but again that stabilizes immediately to the new lower level. Some implementations don't play nicely, but in those cases there's not a whole lot you can do.

I select 90%, try to make most of my changes in one shot before saving, and any degradation is way below the visible threshold. Even if I were to make multiple changes over multiple saves, degradation is still likely below the threshold of perceptibility. JPEG seems to bring out the fear in people, but it's really a pretty solid algorithm, you just have to give it the proper setup.

But Doug's comments certainly are wise to follow as you are starting out.

[Martin Boekers]

a lot depends upon the image for artifacting, in the early days of digital I did some testing with my trusty Canon G2 (about $1100 at the time
YIKES 4megs, my first Apple notebook in 1998 was over $5000. REALLY YIKES 8 gig HD) So I did a bunch of testing Granted it was only a 4meg image
but there were signs of visable degreadation at 3 saves (little compression) by the time you hit 10 saves it looked like most the images I get from clients today:D
Tech stuff as well as file size capture much more info now and may not be as a bad back
then. I see so many work an image than save it over the file print
it then change the file again until they like it
not realizing the should save the orig and work with a copy.

Some of this may not matter as unless you engrave Corian you are not going realize the
resolution. Grain of the wood will lose any artifacting.

Someone here was camparing substrates to resolution a while back with Corian and marble high res and wood lower res. I liked that idea.

[Dan Hintz]

Someone here was camparing substrates to resolution a while back with Corian and marble high res and wood lower res. I liked that idea.
That was likely me, and I think you were the first to comment on it way back when. I consider things like anodized aluminum a high-res substrate, wood low-res, items like granite/marble/glass/plastic low- to medium-res, etc. I match my substrate's possible resolution to the image being engraved, always aiming for a higher resolution in the image if I think it will be used on a higher-res substrate in the future.

[Bill Cunningham]

With the cost of memory being so cheap, and getting cheaper just about every day, I see no point in using any form of compressed image files.. But, the customer with the average digital camera that stores .jpgs can't seem to resist the the temptation of actually being able to take and save 10,000 pictures on a SD Card, and the other setting, only lets him/her take and save 2000 pictures..:D
I usually tell my customers to use the setting that gives them the fewest images on a sd card, and back that up by asking them when was the last time they went anywhere and actually 'took' 2000 pictures:p. The bigger the image I get, the better. I can always make it smaller as needed, but trying to engrave a 200 x 300 pixel image at 8 x 10" is not gonna happen.. As for scanning, I usually use 300 dpi RGB as well.. They only time I have to switch to cmyk is when outputting files for a trade print shop..

[Jim Conley]

I keep trying to respond but the ether appears to be eating my posts.

Jim

[Jim Conley]

I had a detailed response prepared but it disappeared. I received the token expired message.

I there any way I can retrieve the info?

I will gather the details again tomorrow, as I put them into the message, not on a dead tree.


I have been told I would be a Great Procrastinator, but I keep putting it off.

Jim

[Curt Harms]

I had a detailed response prepared but it disappeared. I received the token expired message.

I there any way I can retrieve the info?

I will gather the details again tomorrow, as I put them into the message, not on a dead tree.


I have been told I would be a Great Procrastinator, but I keep putting it off.

Jim

O.T. but for longer posts it's wise to create them in a text editor like notepad for Windows then copy and paste. The likelihood of having problems posting is inverse to the length of the post. Two sentences=no problem 4 paragraphs=problem. Having said that, I can't remember ever having a problem posting to SMC using Firefox. I can remember creating a post, doing a preview and closing the window without clicking the "post" button:o, hence my advice for creating and saving in a simple text format.

[Dan Hintz]

I can't remember ever having a problem posting to SMC using Firefox.
I have... it's a function of SMC, not FF, that usually causes the problem... database going offline, too many inquiries at once, etc.

I can remember creating a post, doing a preview and closing the window without clicking the "post" button:o, hence my advice for creating and saving in a simple text format.
Done that a few times... after typing in two pages and then losing the response, it kinda takes it out of you to retype the whole thing and the thread goes unanswered. Real bummer...

[Doug Griffith]

For long posts or even long emails, I always select all and copy to memory prior to committing. Then, if there's an error, I paste into a text editor and start the process over.