Loupes for analyzing grain and pixelization of printed photos for scanning.
Dec 19, 2017 20:05:09 #
I want to scan some photos but would like to determine the visual quality insofar as grain and pixelization before scanning. I am considering using a loupe for this and would like to know which magnification ratio loupe would provide the equivalent 100% magnification in Photoshop . Also I would like to know, what incrementally sized loupes would be used to determine the range of the visual quality (i.e. 5x, 10x etc.). I've read much documentation concerning PPI and DPI and still have some reading to do but this post is specifically about magnification loupes. The searches I've done on line were not very revealing.
Thank you for your input, it is greatly appreciated.
George.
Thank you for your input, it is greatly appreciated.
George.
Dec 19, 2017 20:10:43 #
geolaval wrote:
I want to scan some photos but would like to deter... (show quote)
You will not find this.
PS CC 1:1 depends on the image pixel size. Your set the scanner DPI, not the other way around. Finding a magnifier to 'predict' just will not work.
Dec 19, 2017 20:33:56 #
ricardo7
Loc: Washington, DC - Santiago, Chile
How are you going to quantify grain and pixilation with a loupe from
one picture to another? What am I missing?
one picture to another? What am I missing?
Dec 19, 2017 23:31:50 #
Reply to Ron and Ricardo.
I'm collaborating with a friend who has scanned documents and photos on a project. The end user finds that some the scanned photo files are grainy. The purpose of my query is not to be able to numerically quantify the exact value but to determine the visual quality of the original. Magnifying the original should be more revealing than with the naked eye. That is why I am trying to determine what loupe magnification is closest to Photoshop 100%. I am thinking of using this after the fact to see the level of grain on the original photo. I hope this explanation clarifies my objective. The original photos were scanned at 1200 DPI. Thanks for replying. I was hoping that loupe users might give an opinion.
I'm collaborating with a friend who has scanned documents and photos on a project. The end user finds that some the scanned photo files are grainy. The purpose of my query is not to be able to numerically quantify the exact value but to determine the visual quality of the original. Magnifying the original should be more revealing than with the naked eye. That is why I am trying to determine what loupe magnification is closest to Photoshop 100%. I am thinking of using this after the fact to see the level of grain on the original photo. I hope this explanation clarifies my objective. The original photos were scanned at 1200 DPI. Thanks for replying. I was hoping that loupe users might give an opinion.
Dec 20, 2017 01:10:40 #
geolaval wrote:
Reply to Ron and Ricardo. br br I'm collaborating... (show quote)
I do not think a loupe is going to do what you want it to do. Is the "grain" actually noise in the image? If the objectionable images are scanned from printed photos, then of course there is going to be some image degradation as part of the transfer process. Imperfections in the prints are only going to be magnified when scanned.
Was it a flat bed scanner? If yes, have it done on a drum scanner.
Dec 20, 2017 02:08:53 #
If you're not too much in a hurry -you are okay waiting a few weeks- just order several loupes of various magnifications from China on eBay. There you can find them for only 2 to 3 Dollars each. That's what I did. 5x, 10x and 20x magnification loupes should do. If you are also planning to view negatives, maybe include a 40x magnification loupe as well.
Dec 20, 2017 06:18:35 #
jeryh
Loc: Oxfordshire UK
Try and find the Leica Loupe; they are still available, and do the job, but they are a tad expensive, but you could always look at second hand ones.
Dec 20, 2017 09:35:18 #
Skip the cheap Chinese loupes, they usually are sharp only in the center, blurry as you view outward. Look for a recognizable brand, preferably with a glass lens. I use an old Fujifilm loupe, 10x, and one from Polychrome, 6x?, who manufactured ortho film for the printing trade. Both show a flat field of focus. The 10x was used to check 35mm negs for sharpness in my film days and should be adequate for your needs.
Dec 20, 2017 09:46:27 #
geolaval wrote:
I want to scan some photos but would like to deter... (show quote)
How do you think this analysis will inform your scanning process?
Dec 20, 2017 09:54:26 #
I use two Fujifilm 10x loupes for glassing my negs and slides.
Dec 20, 2017 10:46:41 #
I've been carrying a 10X "Hastings Triplet" for years. Compact and great optics. Never felt the need for more power.
Dec 20, 2017 11:03:48 #
rook2c4 wrote:
. 5x, 10x and 20x magnification loupes should do. If you are also planning to view negatives, maybe include a 40x magnification loupe as well.
Thanks for your reply it is exactly what I was looking for . From your experience do you know which loupe would more approach a 100% Photoshop magnification on a 6 mpx 4x6 photo? And, would you use this same loupe on a 5x7 and on an 8x10 or larger print.
On my monitor, a 6 mpx 4x6 photo has no perceptible grain in PSE 15, at 100% there is a little grain but it’s adequate for an 8x10 print. At 200% grain is quite present and not acceptable for a larger print. I have intentionally excluded the application of any noise reduction processes.
Dec 20, 2017 11:19:09 #
dsmeltz wrote:
How do you think this analysis will inform your scanning process?
It won't. Please refer to my post replying to Ron and Ricardo at the beginning of this thread. My premise is that if the digital file is grainy after scanning a loupe hopefully will allow a better analysis for the source print than the naked eye. From there, expectations can be better managed. Thanks for your interest.
Dec 20, 2017 11:46:57 #
RWR
Loc: La Mesa, CA
geolaval wrote:
I want to scan some photos but would like to deter... (show quote)
Should be simple enough. Photograph a finely graduated scale, blow it up 100%, and see for yourself how much it was magnified.
Dec 20, 2017 11:49:07 #
[quote=rgrenaderphoto]I do not think a loupe is going to do what you want it to do. Is the "grain" actually noise in the image? If the objectionable images are scanned from printed photos, then of course there is going to be some image degradation as part of the transfer process. Imperfections in the prints are only going to be magnified when scanned.
Thank you very much for your reply. I agree with your evaluation and my objective is to analyze the source print to evaluate the level of noise. Loupe magnification should be superior to viewing with the naked eye.
Thank you very much for your reply. I agree with your evaluation and my objective is to analyze the source print to evaluate the level of noise. Loupe magnification should be superior to viewing with the naked eye.
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