Monday, December 8, 2008

Using the Pentax 14.6MP K20D, how can my 300 DPI printed photos get any better with my Epson R-1800 @ 1440 DPI?

Hi Pentaxian friends,

Here I go again with the Pentax K20D!

I got to think , after writing yesterday's post, that the K20D won't be available forever. There are so many new DSLR cameras being introduced, and Pentax may also introduce a replacement for the K20D soon. I assume that it would have more pixels or a larger Full Frame CMOS sensor, video capabilities, but the bottom line, I'm still very happy with the K20D. I'm seriously thinking of buying another K20D body, brand new and at about half the original price and keep it in the original shipping box, unopened, until my current K20D dies.

The K20D does more than any camera I have ever owned. The K20D, along with the post-processing software available today, renders photographs that cannot currently be improved upon. The K20D sensor produces images that can be enlarged to 11" x 14" for print at 300 Image DPI. The recorded resolution of the sensor is 4672 pixels x 3104 pixels. Divide these numbers by 300 (for a printer with 300 Image DPI resolution) and you get the optimum print size of 10.35" x 15.57" - round that off to standard US print sizes and you get 11" x 14". Actually, I understand that 240 Image DPI is about the maximum resolution that our eyes can discern. The same calculations using 240 Image DPI would thus render prints sized at 12.93" x 19.46", or roughly 13" x 19" which is exactly the maximum size that my Epson R-1800 can print. I don't think that many of us print larger than that very often. Until they re-invent printing technology, my pictures won't get any better than what my K20D gives me. Actually, I am (as photographer) the weakest technical link in the digital picture taking process. The only real benefit I bring to the table is my composition skills, and that needs some constant improvements. But wait...my R-1800 is supposed to print at 1440 DPI according to Epson.

Well, before we continue, let's all understand the difference between Image DPI and Printer ink DPI (dots per inch). One color image pixel requires many printer ink dots. This is why we need a 1440 DPI printer (ink dots) to print an image at 240 to 300 DPI (pixels). Attempting higher resolutions on color printers simply limits the pixel size area, allowing fewer ink dots, which then limits to even fewer possible color tones. We need several ink dots in that space to simulate the correct color of one image pixel. As example, to print one "green" pixel on our inkjets, we know it must mix some blue, some yellow, some white and maybe some black. There is no white ink, white is the paper color. To make green, the printer only has the CMYK (Cyan, Magenta, Yellow, and black and some in-between colors on newer printers), ink colors and so must use a few cyan and yellow ink dots, not necessarily equal numbers of each, to achieve a certain shade of green. To make lighter shades of green, blank white space are used in the right amount. Black ink dots are used to darken colors. The average visual effect of all these individual cyan and yellow ink dots, white paper, and sometimes black ink too, looks green to us. But all of these multiple ink dots represent or simulate the color of only one green image pixel. (I found the above a while back while Googling "Printer resolution". It made sense to me)

So...it doesn't matter if Pentax were to introduce a 50MP DSLR, I am still constraint by the printing technology. Yes, some DSLR cameras can produce better colors, operate in almost darkness with higher sensitivity, take pictures at 10 FPS, but in the end, all these attributes just make a photographer's life a little easier. You can achieve the same picture taking with old fashion know-how and modern post-processing software. In my opinion, the final representation of one's photo quality can only be appreciated when printed.

So go ahead and spend thousands on a new DSLR, in the meantime I will keep taking pictures with my K20D until it dies. Chances are, that print for print and size for size, my printed photographs will be just as good as anyone's printed photographs. When my K20D dies, I will open the box containing my newer K20D, and I will be ready to go, and at half the price I paid for the first one and at a fraction of the DSLR cameras available then, on that future date. I bet you that printers will not make the 13" x 19" photographs much better than they do today. It would seem useless as our eyes won't be able to see the difference.

Thank you for reading,

Yvon Bourque

7 comments:

Odyn said...

Ok, but buy a second body? By the time your K20d dies technology will advance. And you'll pay the same amount of money (which you can deposit now and get some interests) for a brand new Pentax Kxd which will have that extra feature you can use.
And who knows: by then it might get very hard to get spare parts for your 'brand new'/out of date camera. (One important part to consider is battery for example)

Anonymous said...

Obviously you fail to take into account cropping ability.

Unknown said...

My point is that it's no use to have a better camera than the K20D as the printed results will not improve. All other attributes of newer cameras, including the cropping as mentionad by Anonymous above won't change that significantly. With time and skills, you can mimic all other DSLRs capabilities to a point. If you have to crop your image so much, you need to get closer to your subjects. As for the new K20D I would hypothetically purchase, that would be my spare part. I think Digital cameras won't have a useful life as long as the 35mm mechanical cameras.

Anonymous said...

I agree completely with your comments in your article. As for cropping ... you should be cropping when you shoot the image to gain maximum use of the pixels you have.

Anonymous said...

I am confident printing will get better. More inks on current inkjet printers mean that fewer "printer pixels" are being required to render an "image pixel". Some printers now not only have up to 3 black inks (yes, 3 separate shades of black) but can shoot droplets at a range of sizes too meaning each ink has several levels. Light-cyan and cyan, as well as Lm, M and Y make some printers carry a total of 8 or more iks!

And let's not forget e-paper... who knows what crazy devices will appear making most print media obsolete?

Though the K20D will serve you for years to come, there will be a time when you will put it aside. I understand your point though: it will be a long time befor you will need to!

Anonymous said...

It's interesting to note that Scott Kelby, in his books on digital photography and on photoshop maintains that a 6mpx camera can output nice 13"x19" prints and that 8 mpx cameras can produce very respectable 16"x20" prints. He goes on to say "...so who's the 10-12 mpx camera for...suckers, just kidding, 10-12 mpx cameras are meant for pros who print to poster size" What he says has merrit, I sent my brother 2 seperate files from my 6mpx Pentax istDs and he photoshop merged them into a very nice 16 x 48 panorama of the entrance into San Francisco Bay and the Golden Gate bridge.

Unknown said...

Anonymous above,

I agree with that. That's pretty much what this post explains. 6mp. 8mp, 12mp 14mp,or even 50mp, it doesn't really matter, they all will print equally. The bottle neck is not the DSLRs, it's the printing technology.