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Is this how pixels and dpi work?

Is this how pixels and dpi work?

2016-05-10 by Lew Schwartz

My understanding:
A 40mp sensor (for example) produces information for 10mp points of capture due to the fact that the Bayer filter takes groups of 4 input sites (GRGB) to produce a single point of capture record.

If we have a full frame sensor, that would produce (@2:3) a capture of aprox. 2582p x 3873p

Assuming
1. that the printer & software editors output 1 capture datum to 1 dot of print (&I understand that this is not necessarily the case)
-and-
2. that we output to the printer at 360 dots/in

We would have a print of aprox. 7 x 11 inches.

So is the up & down sizing so good that I can produce images of just about any size I want? What';s the practical limit on the up side?

-Lew Schwartz

Re: [Digital BW] Is this how pixels and dpi work?

2016-05-11 by Peter Marshall

Lew,

There is no simple relationship between pixels and printer dots. The camera I use produces 14 bits in each of the RGB channels for each pixel - so each pixel can have 3 x 2^14 states, though most printer software only handles 3 x 2^8 of these.

Ink is basically either on or off - either the printer makes a dot or it doesn't - and images are made by using aggregations of dots in various patterns. Converting between the two systems is a complex matter and some software handles it much better than others. Printer technology also comes into it of course.

Fortunately we don't have to bother too much about it, but simply supply the printer with enough information. For most printers there is little if any difference in supplying files at greater than 300 dpi, which is why this is something of an industry standard.� So all you need is a simple calculation. Divide each of the pixel dimensions by 300 and you get the largest optimum print size.� Though you can make prints quite a bit larger and nobody will ever notice. Use 360dpi if you like, but it really makes very little if any difference.

Currently I use a 32Mp� camera which gives images 7360x4912px. At 300 dpi this will give prints 24.5 x 16.4 inches. I usually make prints around half this size, but going considerably larger isn't a problem.� With the right image you could fill a billboard of your choice.

Peter

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On 10/05/2016 20:26, Lew Schwartz
      lew1716@... [DigitalBlackandWhiteThePrint] wrote:

    

    

      
      
      
My understanding:
        
A 40mp sensor (for example) produces information for 10mp
          points of capture due to the fact that the Bayer filter takes
          groups of 4 input sites (GRGB) to produce a single point of
          capture record.
          


          

          
If we have a full frame sensor, that would produce (@2:3)
            a capture of aprox. 2582p x 3873p�

          


          

          
Assuming

          
1. �that the printer & software editors output 1
            capture datum to 1 dot of print (&I understand that this
            is not necessarily the case)

          
�-and-

          
2. that we output to the printer at 360 dots/in

          


          

          
We would have a print of aprox. 7 x 11 inches.

          


          

          
So is the up & down sizing so good that I can produce
            images of just about any size I want? What's the practical
            limit on the up side?

            

              

                

                  


                  

                  -Lew Schwartz

              

            

          

        

      

      
      

    

    



      

  
Re: Is this how pixels and dpi work?

  
2016-05-11 by michael3442@...

  
I fully agree with Peter Marshall. And I'll add, unless you're a high-end photographer/printer, forget all the nonsense about the terribly degrading effects upsizing an image will create. Do a little experimenting on your own. I have several digital cameras including a 6 mp point and shoot from a dozen+ years ago. I particularly liked one of the vacation pics taken on this camera and decided to work it up in PS. When finished, I resized it to 20x30 inches, sharpened it, and had a poster made at Walgreens (!). It's great and is very hard to distinguish from the image on my calibrated monitor. (BTW, at my Walgreens they have a large format Epson printer using K3 inks, prints are made on Fuji Crystal Archive paper.)

The most important thing I've learned in photography is to confirm widely held opinions with my own testing. Most folks just follow the chatter and soon the chatter becomes the gospel. Test for yourself.



      

  
Re: [Digital BW] Re: Is this how pixels and dpi work?

  
2016-05-11 by Jacques Caron

  
Hi

My two cents; like Michael, I made some 24x36 out of my old 6MP D-70 Nikon (DX Format). The lens was very good (a 18-70mm that I should have kept!) and the prints looked very good, printed on a Epson 7900. Testing resolution vs size helped me understand what's OK and what's not.

I made my own rules so I would be glad with the results. Don't get me wrong, I don't accept  "cheap" prints; I've been a photographer for more than 30 years and I hope I know a bit about printing.

So shed some $, make your own tests and from what you see, stick to your own rules.

Good luck



Jacques Caron




Le 2016-05-11 à 10:19, "michael3442@yahoo.com [DigitalBlackandWhiteThePrint]" <DigitalBlackandWhiteThePrint@yahoogroups.com> a écrit :














 


 



    
I fully agree with Peter Marshall. And I'll add, unless you're a high-end photographer/printer, forget all the nonsense about the terribly degrading effects upsizing an image will create. Do a little experimenting on your own. I have several digital cameras including a 6 mp point and shoot from a dozen+ years ago. I particularly liked one of the vacation pics taken on this camera and decided to work it up in PS. When finished, I resized it to 20x30 inches, sharpened it, and had a poster made at Walgreens (!). It's great and is very hard to distinguish from the image on my calibrated monitor. (BTW, at my Walgreens they have a large format Epson printer using K3 inks, prints are made on Fuji Crystal Archive paper.)

The most important thing I've learned in photography is to confirm widely held opinions with my own testing. Most folks just follow the chatter and soon the chatter becomes the gospel. Test for yourself.


    

     

    
    


          
  
 

    
    
 


    
    
 


    




      

  
RE: [Digital BW] Re: Is this how pixels and dpi work?

  
2016-05-11 by Nigel Richards

  
My understanding is that Fuji Crystal Archive is not an ink jet paper, it is a traditional colour silver halide based paper and can be used in a wet darkroom or the back end of a Fuji  lab printing system.  It won’t work in an Epson large format printer using K3 inks.  

I believe in lab printers it is exposed from digital files by a laser system.  

I have had many prints produced in this way when I have wanted archival quality for exhibitions and my own A3 printer were dye based. 

Cheers

Nigel in the UK
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From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] 
Sent: 11 May 2016 15:19
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: [Digital BW] Re: Is this how pixels and dpi work?

 

  

I fully agree with Peter Marshall. And I'll add, unless you're a high-end photographer/printer, forget all the nonsense about the terribly degrading effects upsizing an image will create. Do a little experimenting on your own. I have several digital cameras including a 6 mp point and shoot from a dozen+ years ago. I particularly liked one of the vacation pics taken on this camera and decided to work it up in PS. When finished, I resized it to 20x30 inches, sharpened it, and had a poster made at Walgreens (!). It's great and is very hard to distinguish from the image on my calibrated monitor. (BTW, at my Walgreens they have a large format Epson printer using K3 inks, prints are made on Fuji Crystal Archive paper.)

The most important thing I've learned in photography is to confirm widely held opinions with my own testing. Most folks just follow the chatter and soon the chatter becomes the gospel. Test for yourself.



      

  
Re: Is this how pixels and dpi work?

  
2016-05-12 by michael3442@...

  
Nigel, thanks for clarifying that. I had assumed they were using an Epson paper so I asked the operator and she said Fuji Crystal after poking around the photo area for a while. I didn't see confirmation with my own eyes so I guess I broke my own rule to not accept what anyone says about photography without confirming myself. Dang. I'll head back there and try again.



      

  
Re: [Digital BW] Re: Is this how pixels and dpi work?

  
2016-05-12 by John Castronovo

  
Fuji Crystal Archive is absolutely not inkjet paper, but a chemical processed silver halide based, dye-coupled photographic paper which is exposed to imaging light before processing. Despite the name, it’s not as archival as pigment inks on fine art paper. Prior to the invention of lasers and LED light sources, we printed Fuji CA paper using enlargers directly from film negatives. We also printed on Kodak and Agfa dye coupled papers of course with varying degrees of success as far as longevity is concerned. 
Show quoted textHide quoted text
From: mailto:DigitalBlackandWhiteThePrint@yahoogroups.com 
Sent: Wednesday, May 11, 2016 7:49 PM
To: DigitalBlackandWhiteThePrint@yahoogroups.com 
Subject: RE: [Digital BW] Re: Is this how pixels and dpi work?




My understanding is that Fuji Crystal Archive is not an ink jet paper, it is a traditional colour silver halide based paper and can be used in a wet darkroom or the back end of a Fuji  lab printing system.  It won’t work in an Epson large format printer using K3 inks.  

I believe in lab printers it is exposed from digital files by a laser system.  

I have had many prints produced in this way when I have wanted archival quality for exhibitions and my own A3 printer were dye based. 

Cheers

Nigel in the UK

 

 

 

From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] 
Sent: 11 May 2016 15:19
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: [Digital BW] Re: Is this how pixels and dpi work?

 

  

I fully agree with Peter Marshall. And I'll add, unless you're a high-end photographer/printer, forget all the nonsense about the terribly degrading effects upsizing an image will create. Do a little experimenting on your own. I have several digital cameras including a 6 mp point and shoot from a dozen+ years ago. I particularly liked one of the vacation pics taken on this camera and decided to work it up in PS. When finished, I resized it to 20x30 inches, sharpened it, and had a poster made at Walgreens (!). It's great and is very hard to distinguish from the image on my calibrated monitor. (BTW, at my Walgreens they have a large format Epson printer using K3 inks, prints are made on Fuji Crystal Archive paper.)

The most important thing I've learned in photography is to confirm widely held opinions with my own testing. Most folks just follow the chatter and soon the chatter becomes the gospel. Test for yourself.



    

  



    
    
    
  

  
  
    

      
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