Digital Photo Processing

[louisg]

Hello all,

I was wondering about where the best place is to get digital prints?

Used Asda and Photobox and found they are very similar in quality.
Is there anywhere anyone reccomends as i would like a higher quality print.

Also can anyone tell me why digital prints are not as good a the old style 24 convential prints please.

louis

 

[Picman]

Louis,

I too have found that print quality can vary widely. My friends and I have started using an independant lab that produces good quality prints, they may not be the cheapest but they maybe worth a look. Try www.fotofactory.co.uk and see what you think.

Picman

 

[senu]

Nice site.

Louis,

I have not used an online service before but have been told good positive things about them

Like you I have used Asda, and in addition Kodak Express ( in Ealing) and an independent Agfa franchise operator in my locality ( Hayes/ Hillingdon) for the past 5 years

I mostly do some basic photoshop work on the images before burning them to CD as the digital "negative"( jpegs).
I do montages and some extensive work in Photoshop/ Photoshop Elements occasionally for larger prints with borders etc.
For a few really special Pics I print off on glossy Photographic paper using a good Epson photoprinter (R300) to have an idea of what to expect. It more than compares favourably with "proper " photographs but is obviously not cost effective for more than a few pics.

Given the same digital "negative"

Asda quality varies from good to so so

Kodak Express usually seems to come out good to very good

My Local Agfa Operator seems to reflect how good or not so good my post processing ( Photoshop) work on the images was. His prints also seem to cut off anything too close to the border. On occasion, quality of his larger prints ( 8"x10" and above) lag behind Kodak Express

It is probably true that the better the jpeg files you give to any of the printing services, the better your prints are likely to be so a little work before they go off will yield benefits. ( dont be scared of a little tinkering as most of the printing labs simply cannot go through and correct every single image b4 printing). Such is the wonder of digital

Because of previously owning a 6 megapixel and now 8 megapixel camera I often wonder how practical it is to upload those big file sizes to an online service.

I know this all sounds inconclusive, but hope there is something useful to learn in them

 

[louisg]

Thank you both for the reply.

Yes i belive there is definately a loss in quality from uploading the image, especially at full size, they just wouldnt have the space available to store images.

Will try that site.

Will also try tinkering with images then burning to cd-r then trying asda etc, to see if photos come any better. I usually just take my memory card down there and just get them printed

So can anyone reccomend a good photo printer for home that can do can also print other things like word documents etc

louis

 

[longleyc]

Louiseg,

The Epson "R" range are good. The Canon Ipixa range are too. Individual ink tanks keep down costs on these models but home printing is expensive by comparison.
I use Kodak Professional Glossy paper for inkjets. Superb results.

Online printing is by far the cheapest and best option for quality I believe. I use www.ofoto.co.uk(Kodak). 100 years of photography experience must mean something!

There are a few reasons why the prints might look poor.
Check your save settings for jpg. You want a low compression setting (1 is high and 12 is low)and thus larger filesize. Save all your original camera jpgs into Tiffs for archiving. Then manipulate the tiffs and save to jpg for printing online.
Convert the image resolution from 72dpi camera default to around 300dpi in software too. As you change the dpi it does affect the print output size so adjust the dpi to the output size you require. (Easy in Photoshop).

Your original camera resolution may be low, you want the biggest output the camera can go. Pixels = quality! If you crop, you lose pixels.

Image noise, i.e. high ISO setting or poor camera sensitivity can creat noise. These pics looks awful no matter the printing quality

Monitor, software,printer calibration incorrect.

There has been whole books written on this topic but there are a few pointers.

Note. Its been estimated that 20 megapixels is needed to reproduce the same quality as 35mm film. The Leaf digital back ( 22MP) costs £17,000. So dont be too hard on yourself with a £500 camera!

 

[Drew2]

So can anyone recommend a good photo printer for home that can do can also print other things like word documents etc

I can totally recommend an Epson PM950C (Stylus) as I have one and the prints are superb. Can print onto cd/dvd directly and thick card. Has 7 ink cartridges so prints a very wide spectrum of colours. Is a few years old now so you should be able to source a 2nd hand one cheap (me local 2nd hand shop had one for 35quid!!) or take the plunge and buy the latest model which now uses 6 colours.

Everyone I have shown my A4 prints too can't believe they come from a home printer.

I found an Epson R220 for very reasonable money brand new on ebay.

This is also nice:http://cgi.ebay.co.uk/EPSON-STYLUS-...851323870QQcategoryZ11203QQrdZ1QQcmdZViewItem

 

[senu]

Louis,
I mentioned the R300( Epson). It is a "6 ink" Photoprinter with a card reader and an ability to print straight off the cards ( A feature which Ive never used) . Like Drew2's it also prints directly onto CD /DVD with printable surface.
For my day to day work I also have an HP photosmart 7350 which is rugged, fast, Does Photos very well but not quite in the same league as the Epson , and a Laserjet for documents,"official" letters

The R300's Photo print quality is excellent. It works best with Epsons Premium glossy paper but you may find that by experimenting and optimising print settings you will find a happy compromise between cost and quality.
Most "avid" printers can easily spend more on ink and paper in the first 3 months than the cost of the printer itself. Alternative inks and Paper are the way to keep costs down. I just avoid using it for volume printing.
Look around for these printers or the more recent ones , they tend to be quite inexpensive.

"longleyc"'s link didnt work so i did a serach for ofoto Im not sure its this one here .

He mentioned changing the dpi setting from screen default of 72dpi to 300 which is the right advice and one of the things you do at home to squeeze every bit of quality from your camera/ printer.
I just wonder how much of a file size for uploading a 8"x 6" or 8"x 10" image at 300 ppi/dpi will be.
My suspicion is that the online service take whatever you send to them then upconvert the resolution onsite as this is seems impractical for you to do prior to uploading ( with many images) ......Unless you are posting your images to them a CD.

 

[RimBlock]

There are a few reasons why the prints might look poor.
Check your save settings for jpg. You want a low compression setting (1 is high and 12 is low)and thus larger filesize. Save all your original camera jpgs into Tiffs for archiving. Then manipulate the tiffs and save to jpg for printing online.

If possible the save directly to tiff or RAW. It may require a bit more work (RAW is better as Tiff files are usually huge but requires more work before the result is printable) but the results mean that you are not compressing the original in the camera, converting to tiff for editing and then recompressing again thus giving two chances for compression artifacts.

Convert the image resolution from 72dpi camera default to around 300dpi in software too. As you change the dpi it does affect the print output size so adjust the dpi to the output size you require. (Easy in Photoshop).

Your original camera resolution may be low, you want the biggest output the camera can go. Pixels = quality! If you crop, you lose pixels.

Ahh, wrong way round I believe. DPI is quality and pixels is size. DPI is the number of dots per inch so increasing the DPI figure increases the density of dots but it is always limited to the 'per inch' specification on size. Increasing the number of pixels does not constrain the image size as the density stays the same so the image size increases.

A 12MP image is larger than a 8MP image, a 72DPI 8MP picture is the same size as a 300DPI 8MP picture.

Printers work on DPI so the greater the DPI the better the quality of the print up to the printers maximum DPI ability.

The one place where pixel count does matter is where you do not have enough pixels to fill the photo paper size and then the software in the printer (or computer) has to increase pixel count by best guess. Filling in pixels from an image size too small will not lead to a better quality image. This also works the other way round too. An image too big will either get cropped or reduced in size by software although taking away information from an image is easier than adding something that is not there so the results are often a lot less noticable.

I am sure there are pixel to inch paper size conversion tables out there (ie. an A pixels by B pixels image equals a 4" by 3" photo).

Regards
RB

 

[senu]

I am sure there are pixel to inch paper size conversion tables out there

Im not so sure about that.
The software can convert an image/ graphics' ppi not dpi which the printer uses. how relevant is thier relationship?

I had this issue when I was asked to submit a graphic made in photoshop at 300 ppi and was told the 300ppi setting was equivalent to dpi as long as the print dimensions remained unchanged

 

[Zone]

I am sure there are pixel to inch paper size conversion tables out there (ie. an A pixels by B pixels image equals a 4" by 3" photo).

As long as you know the image size in pixels then divide this by your dpi.

eg. Canon 300d is 3072 x 2048.
3072/300dpi = 10.24inches
2048/300dpi = 6.83 inches
I've reduced dpi to 250 to get roughly 12x8 A4 size with no discernable loss of quality.

For 6x4 prints @300dpi you'll need 1800x1200.
For 7x5 2100x1500.

 

[RimBlock]

Ok so now it is going to get complicated .

I had this issue when I was asked to submit a graphic made in Photoshop at 300 ppi and was told the 300ppi setting was equivalent to dpi as long as the print dimensions remained unchanged

Yes that makes sense as if the dimensions are staying the same then the density is being changed by adding or subtracting pixels rather then changing the density of pixels already there which would result in the resizing of the image.

Printers tend to work in DPI as it is an output medium that builds a picture via a series of dots. The dots can vary in size. Monitors and cameras work on PPI as they have a static number of pixels per inch which does not change (whether the number of available pixels are used is another matter).

This then leads to the question of PPI changing image size or not. I guess it depends on the software and settings. Are you adding / subtracting pixels or using ones already there. If the latter then a chart should be available, if the former then a chart should also be available but would need to be specific depending on the PPI of the image.

RB

 

[senu]

Hey stop youve me Im dizzy!!

Ok Im with you... But for Louis..

After tinkering,
Decide your print size
and using the resize Photoshop/Photoshop Elements
Put the ppi equivalent of 250- 300dpi and maintain your required print size , constrain proportions and for resample use bicubic
If your image has so much more pixels it will get rid of some with minimal loss in quality

If not, it will interpolate ( by intelligently adding pixels) .This will not increase detail but should prevent existing detail to be lost because of decresed print resolution
This is because the no of pixels per inch at the specified print size compared to the original may have reduced resulting in poor print quality
Confusingly many inkjet printers quote higher resolutions meaning they interpolate themselves:
I would take these claims with a pinch of salt and simply experiment to see which settings give the best picture

 

[Picman]

Louis,

I agree with you that software used by some online labs does compress the image size to speed up the transfer process - resulting in a loss of quality.

The link i posted earlier seems to transmit the original file size without any compression, the down side being that you need a broadband connection as file sizes can be quite large. On the back of the prints you can read the corrections made to each print, this just proves that a person is physically assesing each image before printing, and not just using an auto print function.

Let us know how you get on.

Picman

 

[louisg]

Whooa,

Some really great advice there but most went straight over my head. I will definately make sure i take images at full resolution.
I have decided on getting a Sony P200, any tips on how to set it up?

But with regards to saving images on pc, i honestly can say that i wont have time to tinker with them and save in tiff files etc. It just wont happen.

Im no serious photographer, like the minimum amount of fuss, so use point and shoot cameras. Will try the online photo processor that uploads with highest res, as im ok have 2 meg broadband.

Thanks again for the advice and giving me your time.

Louis

 

[longleyc]

Senu correctly pointed out the www.ofoto change.
Its now renamed http://www.kodakgallery.co.uk/Welcome.jsp.

Thanks senu.

Rim, Sorry you really lost me somewhere.
Dpi isnt about pixel size or quality. Pixel dimensions determine the final output quality, all things being equal. More pixels, more image quality. A PPI change DOES NOT change the image size.

A 2304 x 1728 (4mp) image, is still the same file size at 72dpi or 300 dpi. Dpi really is important when printing only. DPI is printing terminology. PPI is computer screen resolution. Though to often simplify things they can mean the same thing in usage.

At 72dpi, the 2304 x 1728 4mp image will print as 32 inches by 24 inches.
At 300dpi, it prints at 7.68 inches x 5.76 inches. Its still the same file size and resolution, whatever the dpi. Changing the dpi just alters the print dimensions.

Large print dimensions (10"x8")and low resolutions (1600x1200) just result in poor pics. (Not enough pixels to cover the area.)

I been changing my images for years using this method and guaranteeing the image output size I want.

Louise, also make sure that the camera is set to "Fine" on the highest camera resolution. The .jpg format is compressed or lossy format. Fine setting is the least compression. Low compression = larger file sizes= better quality. Lossy formats reduce picture quality. However dont be suprised that some images will naturally be a smaller file size than others for the same resolution. In camera processing (.jpg) will make scenes that have lots of the same colours, ie. Skies, Walls etc smaller in file size naturally. Thats how compression works, without knowing how it works.

 

[RimBlock]

Rim, Sorry you really lost me somewhere.

Yes I think I may have lost most people .

Essentially we are saying the same thing with a couple of exceptions.

Dpi isn't about pixel size or quality.

DPI is not about pixel size or display output but it is about print quality / output size.

Pixel dimensions determine the final output quality, all things being equal.

Depends what you are outputting too (monitor or printer).

More pixels, more image quality. A PPI change DOES NOT change the image size.

Yes it does. More pixels = bigger image unless you change the PPI ratio. Changing the PPI ratio without constraining the picture size will change the size of the displayed image. If you have an image that is 100x100 pixels and = 1" x 1" at 100 PPI(for example) the having a ppi of 50 will change it to 2" x 2" (2"x50PPI = 100 pixels). Having a PPI of 200 with the same image will reduce its size to 1/2"x1/2". This is size as relates to the capacity of the monitor in use. This will not change print size unless the software used is changing the DPI to match the PPI. The image resolution will remain the same but this is not the same as physical size.

A 2304 x 1728 (4mp) image, is still the same file size at 72dpi or 300 dpi.

If you are not constraining the size then of course. You have the same number of pixels to report on so why would the file size change. I think the problem is that you are measuring the image size by pixels rather than a static measurement like inches or centimetres. Physical size cannot be denoted by number of pixels. It depends on the PPI of the display device as to how big the picture will be physically displayed.

Dpi really is important when printing only. DPI is printing terminology. PPI is computer screen resolution. Though to often simplify things they can mean the same thing in usage.

Yep we both agree on this 100%

At 72dpi, the 2304 x 1728 4mp image will print as 32 inches by 24 inches.
At 300dpi, it prints at 7.68 inches x 5.76 inches. Its still the same file size and resolution, whatever the dpi. Changing the dpi just alters the print dimensions..

It is still the same displayed size if the PPI does not change with the DPI. Just as changing the DPI changes its output format size (i.e. printing), changing the PPI changes its output format size (display on a monitor) but it will not physically change the number of pixels in the image unless you constrain the image size (not resolution).

Large print dimensions (10"x8")and low resolutions (1600x1200) just result in poor pics. (Not enough pixels to cover the area.)

Now this depends on the DPI of the picture as you mentioned above. If a picture is set to 1 DPI it does not matter how many pixels it has, it will still look really bad unless viewed from distance (probably a very long distance ).

I think for the most part this is pretty immaterial as most software allows you to choose to change only the DPI values and therefore they are linking the DPI to PPI and changing both.

There is a nice set of charts here which give you an idea of monitors PPI stats depending on resolution / size and aspect ratio of the monitor.

Going any further than this is going to drive me insane and I have a reasonable handle on this .

The problem is there are so many variables that will be specific to the users setup. It is very much like colour profiling where it can get very complex.

Bottom line is that if you keep the dpi to between 200 and 300 you will get good quality shots as long as DPI x size in inches for each side is not greater than the pixel resolution for that side. If it is greater then quality will suffer as the difference increases.

The resolution does not determine the final size but the output device does depending on it's Dpi or Ppi ability / setting. Just don't get me started on the DPI / PPI debate on printers and how the number of inks (i.e. 6) relate to DPI but PPI needs to be divided by the number of inks as the six inks are used to make one final colour dot which would be the equivalent of a views monitor pixel .

Guess I really should do some work now.

RB

 

[senu]

RB ,

that is a really simple answer to " How do I get Good Picture Quality?"

Still ,It reinforces my simple belief about how impractical it can be to upload an image to be printed at say 10" x 12" ( let alone a3) needing printing at 300dpi .Even with broadband that promises to be a slow transfer:
Which infers that when send your image at best quality/ reasonable file size just let the print lab optimise it for printing at whatever size.
Im going to print out that lecture of yours and keep it for reference !!
Still thanks anyway: I expect youve finaly got some work done

 

[RimBlock]

RB ,

that is a really simply answer to " How do I get Good Picture Quality?" :

Ahh but I thought it was about getting the best print quality .

Ok here is the abridged version.

Resolution (xxx pixels by xxx pixels) does not = picture size alone.

DPI is used for printing. Try to keep above 200

If DPI*size in inches > resolution for that side then you will lose quality.

Output size is dependent on the device outputting and its best DPI.

Changing the DPI will change the printed size unless you lock the physical output size and then it will either add or subtract dots (pixels) which will change the resolution (A x B pixels)

Don't worry about PPI

Having an ADSL connection does not mean that files will upload quickly as most connections are limited to 256Mbits with some only being 128Mbits upstream (i.e. to the internet) even if you have a 8Mbit downstream connection.

Ok, hope that is clearer.

RB

 

[longleyc]

Somebody please close this post!!!!!

 

[RimBlock]

As I like to be able to back up what I say I tried the following. Feel free to try yourself.

I opened a pic (12.7MP 2912 x 4368 @ 240 ppi) from cr2 in CS2

Changing the image to 50ppi (image -> image size -> resolution box to 50) changed the resolution to 607 x 910 but the image size stayed the same (32cm x 48cm) so what CS2 is doing is changing the PPI values while maintaining the size of the image by removeing the extra pixels.

Changing the image to 400ppi changed the resolution to 4854 x 7280 and again the image size stayed the same. CS2 is therefore constraining the size and adding pixels to create the requested PPI.

Creating a new document (File -> new).

Height and width as 500 pixels
PPI as 50
Size then equals 25.5 x 25.5cm

PPI as 250
Size equals 5.1 x 5.1 cm

PPI as 500
Size equals just over 2.5 x 2.5 cm

So when you do not constrain the size of the picture then the PPI changes the size depending on your specified pixel resolution.

I am not dissagreeing with Longleyc's technique as it obviously works for him but am just trying to show that there are three distinct factors here, resolution (ppi / dpi) size (pixels) physical size (inches / cm) and that they are all related. Ppi and pixel size define the physical size depending on the softwares settings (no constraint of physical size in example 2) or physical size and ppi/dpi define pixel size (constraining physical size, example 1).

So as seen in example 1 CS2 constrains the physical size if you change the PPI/DPI of a loaded picture so by changing the original DPI/PPI you are adding or removing pixels which will potentially reduce quality of the final picture.

Regards
RB

 

[louisg]

Somebody please close this post!!!!!

Why

 

[longleyc]

Why?

Because after asking questions and getting helpful answers, you said thanks, but im just a point and shoot person! So i guess youre not interested in the technical details for one.
This post was getting increasingly confusing, which wasnt really helping anyones learning curve for such a simple request. Maybe someone was trying to prove a point. Let them.

 

[senu]

"longleyc",

I think the thread has its merits, Your posts have been very helpful and informative.
Even if the OP has developed cold feet, there are others whose unasked queries have been answered.

For instance Im now able to try yours and RBs methods of tinkering with pic sizes resolutions to my hearts content to see what works for me.
I for one find the issue of ppi/dpi a lot clearer than I did even though it seems you each express different points of view.
What I did not state clearly originally was that the ( confusing) ppi/dpi request from the commercial printers was for a graphic I made in Photoshop ( which had a small pic) not a Pic itself.
Being a vector based graphic , unlike digital photo image with fixed resolution, I could alter it with no loss of detail. I just needed to see how this applied to the current " megapixel race" and ease of uploading for online printing . So ....not really off topic
Sometimes the expression " Im a point and shoot person" means "I find this all bewildering" but, "Maybe I can experiment when I feel a lot more confident".
Your guidance and advice will still be as relevant then as it is now

 

[RimBlock]

I think the fact is that both myself and Longelyc are coming to more or less the same point from different directions.

The only 'point' I was trying to make was that there are three factors that interact which is what Longelyc was saying in his original examples but he was only referencing two of them in any one example. I have just been trying to give a more detailed view.

There is information here for the more technically minded but also summaries for people who just want a brief idea.

Now, longelyc, if you disagree with the information I have provided then please say so. I am not and have never claimed to be an expert. This is my understanding from the research and experimentation I have done and the results I have seen.

I am not in to 'butting heads' but would be interested in others opinions. You have provided informed and helpful information in the past so it just seems strange that you seem to have taken the perceived view of 'your wrong and I wont even discuss it'.

Any-hoo
Lets all just
RB

 

[louisg]

Why?

Because after asking questions and getting helpful answers, you said thanks, but im just a point and shoot person! So i guess youre not interested in the technical details for one.
This post was getting increasingly confusing, which wasnt really helping anyones learning curve for such a simple request. Maybe someone was trying to prove a point. Let them.

Well im sorry if i offended you. I honestly didnt mean too.
I am very interested, but i find it very confusing to be honest. My new camera is on order from amazon Sony p200, and i will see how i get on. Senu is right what he/she said. i am bewildered.

Im a truely greatful for all replys. If i find that i am getting on ok, i will practise with some of the tips.

Regards
Louis