The canonical tag is used for WP pages because the same page is available multiple ways. No-index would be added to the non-preferred versions of URLs like /archives/ or /tags/ or /category/, depending on the site's preferred URL format. If there was only one version of each, then it wouldn't make much sense.

But if it is a gallery page, it is better to use a canonical tag to the article url or simply a noindex tag?

Google recommends that you do not use noindex and canonical on the same page.

John Mueller from Google on noindex and canonical together
http://www.seroundtable.com/noindex-canonical-google-18274.html [seroundtable.com]

This is the best practice that should be followed if possible.

On the other hand I have not seen a page that was harmed by doing this and where fixing this would have some kind of "recovery". I am guessing that the worst that could happen is that Google ignores one or the other or both.

[edited by: aakk9999 at 11:37 am (utc) on Apr 15, 2014]

@aakk9999 what about this: But if it is a gallery page, it is better to use a canonical tag and pass all the link juice to the article url or simply a noindex tag?

I would use noindex or block it in robots (depends on what URLs are exposed without going further to gallery).

Noindex will transfer the juice to the site, but not to a particular page.

So, in my case i have example.com/gallery/article_url and want to use a canonical that points to example.com/article_url.

Wouldn't this be a better solution?

Please read the FULL text of what John Mueller said. He said not to use canonical with "no index no follow". The no follow part is the problem - it's telling googlebot not to follow your canonical link.

I see no problem with no index on a page with a canonical tag. The problem is when there's a no follow tag.

The problem is when there's a no follow tag.

This is not how I understood it.

Mention of "nofollow" is in the question to John Mueller, but not in John's answer. In his answer John only mentions co-existance of noindex and rel=canonical being problematic. He did not refer to nofollow at all.

@andrewc
What kind of content is on the gallery versus on the article? If the content is not similar (and I guess it is not, one is article the other is photos), you should not really use rel=canonical.

You do have a point here Jay5r.

I read this: "The issue is the no index causes you to loose the rankings instead of transferring them. But if that is OK with you then it is fine. The main point is that you should not have both on the same page, they conflict. "

i want to transfer the rankings. If i want to do this, do i simply use the canonical tag to the article url? If i do this, will the gallery pages also be dropped out of the index?

@aakk9999 In the article i have a text about some gadgets and in the gallery pictures with those gadgets.

Shouldn't i use canonical tag? If not, why?

You supposed to use rel=canonical for the pages that are very similar. In your case this is not true as one is article and the other is picture gallery.

With regards to "transferring rankings" - do your gallery pages rank at the moment? Or do you think of allowing link juice to circulate to the rest of the site?

With noindex it will still circulate and the site will get the benefit of links to gallery page, but this will spread to the whole site. With canonical, this benefit would concentrate to the page you set in your canonical.

To me, using rel=canonical on picture gallery to capture link juice and forward it to the Article page by implementing rel-canonical may be seen as manipulative by Google. On the other hand, webmasters make all kind of mistakes with rel=canonical implementation, so if Google thinks it is not right, they may just ignore it.

Couple of resources worth reading:

Specify your canonical
http://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html [googlewebmastercentral.blogspot.com]

Is it okay if the canonical is not an exact duplicate of the content?
We allow slight differences, e.g., in the sort order of a table of products. We also recognize that we may crawl the canonical and the duplicate pages at different points in time, so we may occasionally see different versions of your content. All of that is okay with us.

5 Common Mistakes Webmasters do with rel=canonical
http://googlewebmastercentral.blogspot.com/2013/04/5-common-mistakes-with-relcanonical.html [googlewebmastercentral.blogspot.com]

Ok, so i will answer you at the first question: yes, the gallery pages rank at the moment, but i want visitors to focus on the article itself.

Let me ask you something: can't my problem be compared with this:

[dc8hdnsmzapvm.cloudfront.net...]

aakk9999 i think you are right here. I do have an article and a gallery. So guess the best thing would be to use noindex, follow. Right?

The answer is not straight forward as everybody's circumstances are different.

The question here is whether you think that many gallery pages are damaging the ranking of the rest of your site.

If gallery pages rank, I would also look whether (and how much) traffic gallery pages are bringing at the moment and are they ranking at the expense of article pages.

If they bring some traffic, do not compete with article pages and the site is not suffering in general because of them, then I may consider leaving them accessible and indexable and perhaps changing them to add a nice inviting button saying something like "Liked the photos? Find out more!" or similar to try to channel that traffic to article pages.

If they do not bring much traffic, or they rank at expense of article pages, or they overpower the site, I would consider noindexing them.

OK, thanks very much for clearing that up aakk9999!

For future use I would like to point out the original discussion with John Mueller:
[plus.google.com...]