PSD or jPEG= confused??

[gtirman]

Over the years i have been getting my images printed at a normal downtown shop who have Jpeg or PSD options. As i shoot in Raw and after a little sharpening ,color enhancing etc i give the images to them in PSD format. [8 bit ]
However i have been told of a professional Lab who supposedly do great work and who are cheaper......however they only allow Jpeg in sRGB.

All things being equal which one should produce the better quality print?
It seems odd to me that one has adjusted in Photoshop and then converts back to a Jpeg which is surely on the lower rung in formats.

Am i missing something?
Any tips appreciated :}

[GeoffWessex]

If you're lowering your bit-depth to 8-bit, you may as well go the Jpeg route, with minimal compression. sRGB happens to be the most common colour space used by commercial printers (even though, technically, AdobeRGB would be better for printing with).

Put another way.........

A PSD can be 16-bit and would then be better quality than a Jpeg, which has to be 8-bit. But if your PSD is only in 8-bit anyway, a Jpeg with no compression is just as good.

More to the point, commercial printers are gradually all coming around to Jpegs in sRGB. They may not even be able to handle anything different now - like colour negatives became 'the norm' years ago and you had to pay double for the much simpler processing of B&W - just because it was different and didn't follow their normal workflow.

[chris-p]

Originally Posted by gtirman

All things being equal which one should produce the better quality print?

That really depends on what you're printing on and how but if you're printing below the native resolution of the picture you're unlikely to ever notice a difference. In theory, the PSD should give you a better print if you're pushing the resolution of the picture but you'd be hard pressed ever to actually see it.

There are 2 big reasons why printers prefer JPEGs. The first is file size. The second is that JPEGs are "flat" (that is, you don't get any layers). On which note...

Originally Posted by GeoffWessex

If you're lowering your bit-depth to 8-bit, you may as well go the Jpeg route

I don't completely agree with this - I keep everything as PSD because JPEG doesn't support layers. If you've been busy in post and you want to maintain the individual integrity of the adjustments you need to use something that keeps the layers intact.

[KeithT]

I never use PSD files unless an image I am working on has many layers and I need to continue working on it at some other time. PSD file extension = smaller file size with layers. However, for storing masters I tend to use Tiff, and for prints at 8 bit I use uncompressed jpeg.

[gtirman]

Unfortunately my PSD printers can only use 8 bit. I thought that every time one saves to JPEG that some quality/data is lost and this is why i stick to PSD.

Correct me if i'm wrong here however would not a PSD at say 50 mb have more info data [better quality/color etc ] than say a Jpeg at 5mb ???

[MattUK]

Originally Posted by gtirman

Unfortunately my PSD printers can only use 8 bit. I thought that every time one saves to JPEG that some quality/data is lost and this is why i stick to PSD.

Correct me if i'm wrong here however would not a PSD at say 50 mb have more info data [better quality/color etc ] than say a Jpeg at 5mb ???

It's more a case that every time a JPG is re-saved, it loses quality.

But it's all relative to what you're trying to achieve.

If you have a massive resolution image, and you're trying to print it on a postage stamp, it doesn't matter how lossy your save method is - it's still going to print crystal clear.

If, however, you're trying to print an A5 sized image at A4 (double the size), then retaining every ounce of quality is essential.

[GeoffWessex]

I'm not suggesting deleting the PSD and its layers.... just making a high-quality jpeg of it for commercial printing. I'd still retain the PSD (or TIFF) as the 'Master', but make Jpeg versions as required. If the commercial printer wants Jpeg that's what you have to send.... but go for minimal compression.

[gtirman]

I hear what you are saying Geoff and i appreciate it very much however i will revert back to my original question in a nutshell

Commercial printerallows only Jpeg. My existing printer does PSD albeit only at 8 bit.
Which operator should give me the best print? [all else being equal ]
Prices are exactly the same.
All my images are printed 8x12 I shoot in the RAW

[MattUK]

All things being equal, the PSD will provide a tiny bit of additional quality at that print size, that the human eye could never even see.

Does that answer your question?

[chris-p]

Originally Posted by MattUK

It's more a case that every time a JPG is re-saved, it loses quality.

Thats not strictly true... JPEGs will only discard data if you force them into either generating a new MCU, performing the discrete cosine transformation again or running their colour space conversion again.
In effect, if you open a JPEG and just save it, or save as, using the same packet settings it won't discard data.