How to reduce JPEG file size

[Guest]

Hey folks,

I do have a file with just one layer and a size of about 20 x 15 cm at 300 dpi.

If I safe that file as a JPEG, the JPEG becomes about 30 MB large.

Does anybody know, how I may reduce the file size without reducing the dpi as well as the quality of that JPEG?

Do I have to change some pre settings or is there an other way?

By the way, I work with OS X Yosemite on my MAC and Photoshop CC.

Thanks in advance.

Regards Nina

[c.pfaffenbichler]

Is there superfluous Ancestors Metadata (see File > File Info > Raw Data)?

Inflated JPG File Size - Photoshop Document:Ancestors Metadata

[Stephen Marsh]

That would be my guess as well:

Prepression: Metadata Bloat – photoshop:DocumentAncestors

[c.pfaffenbichler]

Yeah, there seem to have been a couple of threads on this lately.

Though I am still unclear on how exactly that problem gets triggered originally, when and how an individual file starts accumulating the offending metadata like this.

[Stephen Marsh]

Please forgive the copy/paste job:

This metadata is added as a record of copy or placed document ID entries. Generally, this metadata is small and does not greatly impact the file size of Photoshop or other file formats containing this historical metadata. However, some users have reported files with excessive amounts of this metadata. What is considered excessive? Metadata does not add that much to file size, does it? Well in some cases 100,000 lines of photoshop:DocumentAncestors metadata has been found! A 65mb file may be reduced to 110kb once this metadata has been removed. Writing photoshop:DocumentAncestors metadata to a file is not a bug, however I find it hard to believe that an average user could intentionally perform actions in the normal course of working an image that would result in 100,000 entries taking place.

[c.pfaffenbichler]

But how does it start for a particular file?

Is it some particular History Log Preferences setting for example or something else?

I’ve noticed that the metadata seems to accompany copied composite content through the clipboard for example (not Channels content, though), so that can easily accumulate, I guess.

[Stephen Marsh]

Copy/paste or file/place.

I believe that Adobe staff have commented in these forums that the data is “forensic” in nature and not intended for the “average user”. A composited image may be identified from one or more separate source images using the document ID information.

Scroll down to “Ancestors” in the following link:

http://www.hackerfactor.com/blog/index.php?/archives/2013/05/23.html

There does not appear to be a lot of information out there on this topic.

[D Fosse]

There is no free lunch. To reduce file size, you either have to reduce pixel dimensions, or increase the jpeg compression rate.

That said, it sounds as if you're setting quality to 12/max. There's never any reason to do that - if you need that high quality, you wouldn't use jpeg to begin with. You'd use TIFF.

A quality setting of around 8 is usually good enough, while at the same time reducing file size dramatically.

EDIT: forgot all about the metadata issue. Yes, check that first.

[angie_taylor]

I still love the Save for Web (Legacy) feature if I really. need to get the file size down. It allows for more experimentation  with compression settings. You could also try GIF. If the colours are fairly flat it can be a good option. You can rereduce the file size are you reducing the number of colours that are used in the image. You can also try PNG to see if that gives you better results. If you do need to use JPEG then the save for web feature gives you a better amount of control and the standard savers JPEG option.

Hope this helps,

Angie Taylor – Creative Cabin

[c.pfaffenbichler]

If I remember correctly Photoshop embeds no Colour Profiles in Save for Web-created PNGs and GIFs, so depending on circumstances that could be a risky choice.

[D Fosse]

Actually they fixed that for PNG, both in Save For Web and Export. They both embed the profile now. As long as you remember to check the box, of course. Why it should be unchecked by default is still a mystery.

GIF I don't know, I suspect the format doesn't support icc profiles in the first place.

[angie_taylor]

I guess it depends on what it will be used for. I presumed that, if the user was outputting a jpeg that it was t for print but for web delivery or broadcast - in which case it would probably be fine 🙂

[Guest]

In deed, it is for printing.

I work as a dvd cover designer an I do have the problem with a 3 dvd box,

wich will be printed and folded to include the 3 dvds.

The quality is set to 8, so I am desperate because of the size.

My colleagues who work with Windows use Infran View to reduce the size, somehow it works,

that the file size increases and the quality is still perfect for print media.

Unfortunately that program is available fro Windows only, as far as I could find out.

Any ideas?

Regards Nina

[angie_taylor]

Personally I wouldn't use JPEG for print. The colours would not be consistent and with that much JPEG compression the image quality may suffer. Can you use Tiffs?

[angie_taylor]

Why does the file size have to be so small? How about sending them PDF of the design?

[D Fosse]

Jpeg will work fine for print, except in some special cases with very smooth color gradients (which may show banding in jpeg).

Nina, have you tried what was discussed above - stripping the metadata with Save For Web or Export?

[Stephen Marsh]

JPEG file sizes vary depending on content, however with the quality level and other info provided, I would expect the file to be around 7mb in RGB and around 11mb in CMYK. Depending on whether there is an ICC profile embedded in the image, this may add a small or larger amount of data to the image (depends on the profile). Anyway, this should not be around 30mb.

Photoshop does offer Export and Export/Save for Web options that do feature the ability to strip metadata from saved files. For many users, these standard options make sense and work as required. However for other users, final file formats, colour modes, bit depth and other factors may rule out the use of these “internet” based export options. These users need alternatives, which is where the methods listed on my blog are helpful as they don’t degrade the JPEG by decompressing/recompressing the image data.

[c.pfaffenbichler]

Any ideas?

Have you even checked out the link in post 1 and the Photoshop Script offered there?

[Derek Cross]

Save for Web in Photoshop CC 2015

[jonathancribeiro]

How To Reduce Image Size without Losing Image Quality in Photoshop - YouTube

This video does a good job at showing how to reduce the file size

[billyr80792616]

File > Export > Save for Web (Legacy)

Then you can choose JPEG High, Medium, or Low to adjust the image size

This option works best!

[Lumigraphics]

This is a seven year old post and you are spamming a link to a website.