LED Illumination Comparison

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
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LouiseScot
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LED Illumination Comparison

#1 Post by LouiseScot » Tue May 24, 2022 5:35 pm

As I just upgraded my Amscope T680A to LED, I thought I'd post a quick comparison with the factory fitted T720 LED and with daylight. All images taken at 10x and using the little Toupcam 5MP USB2 EP camera. Also with Sharpcap v4 capture software. The Toupcam was connected to the T720 via an eyepiece tube and to the T680 via the trinocular tube. I just used a small mirror to catch the overcast daylight from the East. All specimens were (Chinese) prepared slides - not the best, but still. All reduced to 30% of original size.

Spirogyra

T720 LED:
T720 Spiro 10x_00002_30pc.jpg
T720 Spiro 10x_00002_30pc.jpg (79.38 KiB) Viewed 4598 times

T680 LED (Adjusted hue -> green:)
T680 Spiro2 10x_00001_30pc.jpg
T680 Spiro2 10x_00001_30pc.jpg (76.11 KiB) Viewed 4598 times

T680 Day:
T680 Day Spiro_00002_30pc.jpg
T680 Day Spiro_00002_30pc.jpg (73.6 KiB) Viewed 4598 times



Will attach some more in a second post :)


Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: LED Illumination Comparison

#2 Post by LouiseScot » Tue May 24, 2022 5:41 pm

Human skin

T680 LED
T680 Skin 10x_00001_30pc.jpg
T680 Skin 10x_00001_30pc.jpg (74.54 KiB) Viewed 4597 times
T680 Day
T680 Day Skin_00001_30pc.jpg
T680 Day Skin_00001_30pc.jpg (72.23 KiB) Viewed 4597 times
T720 LED
T720 Skin 10x_00001_30pc.jpg
T720 Skin 10x_00001_30pc.jpg (82.27 KiB) Viewed 4597 times
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: LED Illumination Comparison

#3 Post by LouiseScot » Tue May 24, 2022 5:43 pm

Maize

T680 LED
T680 Maize 10x_00002_30pc.jpg
T680 Maize 10x_00002_30pc.jpg (105.04 KiB) Viewed 4597 times

T680 Day
T680 Day Maize_00001_30pc.jpg
T680 Day Maize_00001_30pc.jpg (89.22 KiB) Viewed 4597 times

T720 LED
T720 Maize 10x_00001_30pc.jpg
T720 Maize 10x_00001_30pc.jpg (125.51 KiB) Viewed 4597 times
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: LED Illumination Comparison

#4 Post by LouiseScot » Tue May 24, 2022 5:50 pm

From the above, you can see that unfiltered daylight is always bluer than either LED. It's not clear how much the camera itself plays a part in the colour rendition but not an issue for comparison purposes. The Sharpcap capture software (for astronomy really...) allows quite a bit of colour adjustment ahead of capturing single files though I think I only adjusted the hue for the T680 LED Spirogyra. The option is there to adjust the colour/brightness/contrast as well as exposure, gain, white balance, gamma in Sharpcap.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: LED Illumination Comparison

#5 Post by apochronaut » Tue May 24, 2022 6:02 pm

What do you mean by daylight?

LouiseScot
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Re: LED Illumination Comparison

#6 Post by LouiseScot » Tue May 24, 2022 6:06 pm

apochronaut wrote:
Tue May 24, 2022 6:02 pm
What do you mean by daylight?
A cloudy sky
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

SWmicro
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Re: LED Illumination Comparison

#7 Post by SWmicro » Tue May 24, 2022 6:17 pm

LouiseScot wrote:
Tue May 24, 2022 5:50 pm
From the above, you can see that unfiltered daylight is always bluer than either LED. It's not clear how much the camera itself plays a part in the colour rendition
A surprising amount of blue.

As an astronomer you do know that all such astro equipment comes with free clouds :)
So, , , a use for those clouds at last !!! What do you get when you point your camera + 'scope at the free clouds ?
I would expect white (aka northlight)

SWmicro
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Re: LED Illumination Comparison

#8 Post by SWmicro » Tue May 24, 2022 6:26 pm

SWmicro wrote:
Tue May 24, 2022 6:17 pm
camera + 'scope
I mean your astro scope

LouiseScot
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Re: LED Illumination Comparison

#9 Post by LouiseScot » Tue May 24, 2022 6:28 pm

SWmicro wrote:
Tue May 24, 2022 6:17 pm
LouiseScot wrote:
Tue May 24, 2022 5:50 pm
From the above, you can see that unfiltered daylight is always bluer than either LED. It's not clear how much the camera itself plays a part in the colour rendition
A surprising amount of blue.

As an astronomer you do know that all such astro equipment comes with free clouds :)
So, , , a use for those clouds at last !!! What do you get when you point your camera + 'scope at the free clouds ?
I would expect white (aka northlight)
I would expect 'white' but at a higher colour temperature than the LED and which would be variable. I suppose one advantage of an LED is that the colour temperature is fixed for a particular device. But that colour temperature will be determined by the stimulating/blue wavelength and the stimulated wavelengths determined by the emitting phosphors, I think. If I was of a mind to I could dig out my slit spectrometer, get it up and running again, and point it at some LEDs... :)

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: LED Illumination Comparison

#10 Post by apochronaut » Tue May 24, 2022 6:48 pm

LouiseScot wrote:
Tue May 24, 2022 6:06 pm
apochronaut wrote:
Tue May 24, 2022 6:02 pm
What do you mean by daylight?
A cloudy sky
How did you get the light to the slide.

LouiseScot
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Re: LED Illumination Comparison

#11 Post by LouiseScot » Tue May 24, 2022 6:51 pm

apochronaut wrote:
Tue May 24, 2022 6:48 pm
LouiseScot wrote:
Tue May 24, 2022 6:06 pm
apochronaut wrote:
Tue May 24, 2022 6:02 pm
What do you mean by daylight?
A cloudy sky
How did you get the light to the slide.
Via a small mirror - I did explain at the start of the thread...
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

dtsh
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Re: LED Illumination Comparison

#12 Post by dtsh » Tue May 24, 2022 6:55 pm

LouiseScot wrote:
Tue May 24, 2022 6:28 pm
I would expect 'white' but at a higher colour temperature than the LED and which would be variable. I suppose one advantage of an LED is that the colour temperature is fixed for a particular device. But that colour temperature will be determined by the stimulating/blue wavelength and the stimulated wavelengths determined by the emitting phosphors, I think. If I was of a mind to I could dig out my slit spectrometer, get it up and running again, and point it at some LEDs... :)

Louise
I'd be interested in seeing that thread.

LouiseScot
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Re: LED Illumination Comparison

#13 Post by LouiseScot » Tue May 24, 2022 6:59 pm

dtsh wrote:
Tue May 24, 2022 6:55 pm
LouiseScot wrote:
Tue May 24, 2022 6:28 pm
I would expect 'white' but at a higher colour temperature than the LED and which would be variable. I suppose one advantage of an LED is that the colour temperature is fixed for a particular device. But that colour temperature will be determined by the stimulating/blue wavelength and the stimulated wavelengths determined by the emitting phosphors, I think. If I was of a mind to I could dig out my slit spectrometer, get it up and running again, and point it at some LEDs... :)

Louise
I'd be interested in seeing that thread.
You mean the output of a spectrometer? Um, don't hold your breath!
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: LED Illumination Comparison

#14 Post by apochronaut » Tue May 24, 2022 7:18 pm

I'm not sure what the purpose of including an amorphous light source such as a cloudy sky is in your comparison. Microscope condensers have a focal point and with modern microscopes it is finite rather than infinite. Older microscopes that used remote illuminators or the sky, had condensers with an infinite front focal point and a finite back focal point.

Regarding your other illuminator choices, the only image that is passably decent is the last one. It seems to have some contrast and resolution plus a degree of colour separation. There is a lot of blur. Very weak resolution in general.
It is difficult to use such heavily stained slides for any meaningful critical evaluation because you have no baseline upon which to make an evaluation.
Use unstained samples. You might check your condenser focus and diaphragm adjustments. Something is really off besides the quality of the slides.

LouiseScot
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Re: LED Illumination Comparison

#15 Post by LouiseScot » Tue May 24, 2022 7:35 pm

apochronaut wrote:
Tue May 24, 2022 7:18 pm
I'm not sure what the purpose of including an amorphous light source such as a cloudy sky is in your comparison. Microscope condensers have a focal point and with modern microscopes it is finite rather than infinite. Older microscopes that used remote illuminators or the sky, had condensers with an infinite front focal point and a finite back focal point.

Regarding your other illuminator choices, the only image that is passably decent is the last one. It seems to have some contrast and resolution plus a degree of colour separation. There is a lot of blur. Very weak resolution in general.
It is difficult to use such heavily stained slides for any meaningful critical evaluation because you have no baseline upon which to make an evaluation.
Use unstained samples. You might check your condenser focus and diaphragm adjustments. Something is really off besides the quality of the slides.
It was just quick and dirty comparison between my diy LED add-on and the other, factory installed, LED. The mirror + sky was a bit of an afterthought just to see what the colours might be like compared to LED. Obviously there's more green and blue in daylight. The image outcomes are a good enough guide for me.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Greg Howald
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Re: LED Illumination Comparison

#16 Post by Greg Howald » Wed May 25, 2022 4:10 am

Thanks Louise. You just proved that my leds are less blue than daylight. I appreciate that and have more appreciation for the lighting I have chosen, which is very similar to yours. I don't have a 680 yet and maybe never will. But my conversion of my 660 gives similar results. :)
Greg

MichaelG.
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Re: LED Illumination Comparison

#17 Post by MichaelG. » Wed May 25, 2022 8:42 am

LouiseScot wrote:
Tue May 24, 2022 6:28 pm

I would expect 'white' but at a higher colour temperature than the LED and which would be variable. I suppose one advantage of an LED is that the colour temperature is fixed for a particular device. […]
Please forgive the pedantry, Louise … but I must point out that ‘colour temperature’ is not a particularly reliable concept when considering LED outputs. [yes, I know that suppliers quote it]

By definition, it assumes that the source is a Black Body radiator …

MichaelG.

.

This is a very helpful page: https://www.lrc.rpi.edu/programs/nlpip/ ... tisCCT.asp
Too many 'projects'

LouiseScot
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Re: LED Illumination Comparison

#18 Post by LouiseScot » Wed May 25, 2022 8:56 am

MichaelG. wrote:
Wed May 25, 2022 8:42 am
LouiseScot wrote:
Tue May 24, 2022 6:28 pm

I would expect 'white' but at a higher colour temperature than the LED and which would be variable. I suppose one advantage of an LED is that the colour temperature is fixed for a particular device. […]
Please forgive the pedantry, Louise … but I must point out that ‘colour temperature’ is not a particularly reliable concept when considering LED outputs. [yes, I know that suppliers quote it]

By definition, it assumes that the source is a Black Body radiator …

MichaelG.

.

This is a very helpful page: https://www.lrc.rpi.edu/programs/nlpip/ ... tisCCT.asp
Thanks, yes I know - I've studied physics :) . But in this case it's still useful when comparing to different light sources that have variable colour temperatures.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Hobbyst46
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Re: LED Illumination Comparison

#19 Post by Hobbyst46 » Wed May 25, 2022 9:38 am

Jumping late on the wagon...

A 6000+ K cool white LED has an intense blue component. An amber filter (KR12) removes much of the blue so the output resembles a warm white LED.
This is what I have used in the past.
Recently I got a neutral white LED, 4000K or 5000K I think, that has a CRI of ~95, in a commercial retrofit to my microscope. It yields pleasantly white background, where the blue component is small.

LouiseScot
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Re: LED Illumination Comparison

#20 Post by LouiseScot » Wed May 25, 2022 10:08 am

Hobbyst46 wrote:
Wed May 25, 2022 9:38 am
Jumping late on the wagon...

A 6000+ K cool white LED has an intense blue component. An amber filter (KR12) removes much of the blue so the output resembles a warm white LED.
This is what I have used in the past.
Recently I got a neutral white LED, 4000K or 5000K I think, that has a CRI of ~95, in a commercial retrofit to my microscope. It yields pleasantly white background, where the blue component is small.
Yeah the higher the apparent temperature the stronger (and shorter?) the blue stimulating wavelength. I went for the warm white because the blue is relatively reduced but most of the rest of the visible power spectrum output is quite good. I'm not overly bothered by how accurately colours are reproduced by the LED as they can be adjusted on camera, or post capture. I also still have the option of using a halogen bulb on the T680. Most of the specimens I might image don't have much colour anyway! It's clear that LED lighting causes colour shifts when that light is reflected from a coloured surface https://reader.elsevier.com/reader/sd/p ... 0525100155

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Hobbyst46
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Re: LED Illumination Comparison

#21 Post by Hobbyst46 » Wed May 25, 2022 10:18 am

Thanks for the link, Louise!

MichaelG.
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Re: LED Illumination Comparison

#22 Post by MichaelG. » Wed May 25, 2022 10:51 am

[quote=LouiseScot post_id=122568 time=16534733

Yeah the higher the apparent temperature the stronger (and shorter?) the blue stimulating wavelength. ...
[/quote]

Please correct me if I am wrong... But: I believe the significant difference is in the choice of phosphors, not the blue exciter.

MichaelG.
Too many 'projects'

LouiseScot
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Re: LED Illumination Comparison

#23 Post by LouiseScot » Wed May 25, 2022 11:32 am

MichaelG. wrote:
Wed May 25, 2022 10:51 am
[quote=LouiseScot post_id=122568 time=16534733

Yeah the higher the apparent temperature the stronger (and shorter?) the blue stimulating wavelength. ...
Please correct me if I am wrong... But: I believe the significant difference is in the choice of phosphors, not the blue exciter.

MichaelG.
[/quote]

Yes, I think you're right, Michael! See fig 3 here https://www.digikey.co.uk/en/articles/d ... white-leds
I think I had it in my head that the blue wavelength would determine the highest apparent temperature value but it appears to be more complicated than that! Anyway, no worries.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

MichaelG.
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Re: LED Illumination Comparison

#24 Post by MichaelG. » Wed May 25, 2022 1:14 pm

As we’re in agreement, Louise … I am referencing this recent post from another discussion:
viewtopic.php?p=121805#p121805
purely for the benefit of any newcomers who might not immediately recognise the difference between the phosphors.
… it might make the shopping easier !!

Obviously there are different ‘recipes’ available, but the general principle is evident.

MichaelG
Too many 'projects'

SWmicro
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Re: LED Illumination Comparison

#25 Post by SWmicro » Wed May 25, 2022 8:01 pm

apochronaut wrote:
Tue May 24, 2022 7:18 pm
Microscope condensers have a focal point and with modern microscopes it is finite rather than infinite. Older microscopes that used remote illuminators or the sky, had condensers with an infinite front focal point and a finite back focal point.
Interesting.
How can I tell which type of condenser I have ? ( I think my mirror & condenser are from different sources)

apochronaut
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Re: LED Illumination Comparison

#26 Post by apochronaut » Thu May 26, 2022 1:11 am

Some companies kept infinity corrected condenser designs from the past but any of the modern Chinese ones I have looked at are finite. An infinity corrected condenser should be just as good as a finite condenser as long as the illumination beam is parallel and köhler systems. Finite condensers are obviously better at focusing on close diverging light beams.
To check them , just set the condenser back lens at focus on a grid or piece of fabric for instance and while backing away from it, it should maintain focus from quite close to several feet and beyond. A finite condenser will have a point of focus and be increasingly blurry inside that point.
I just checked some AO condensers, a 1.3 achromat aplanat from 1925, a 1960 abbe, 1960 abbe phase condenser and 1985 abbe aspheric and they were all infinity. A good quality W.F abbe from an approx. $1500.00 Chinese infinity corrected fluorescence microscope sold by Changsa Suny was finite.

LouiseScot
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Re: LED Illumination Comparison

#27 Post by LouiseScot » Thu May 26, 2022 11:02 am

Here are the same slides taken on the T680 with the 20W halogen bulb.

Spirogyra
Hal Spiro 10x_00001_30pc.jpg
Hal Spiro 10x_00001_30pc.jpg (70.9 KiB) Viewed 4236 times

Skin
Hal Skin 10x_00001_30pc.jpg
Hal Skin 10x_00001_30pc.jpg (65.49 KiB) Viewed 4236 times

Maize
Hal Maize10x_00001_30pc.jpg
Hal Maize10x_00001_30pc.jpg (99.66 KiB) Viewed 4236 times

I didn't use a blue filter and the bulb brightness was mostly set to about 60% max (I think!). As before all images set to 30% of actual size.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

SWmicro
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Re: LED Illumination Comparison

#28 Post by SWmicro » Thu May 26, 2022 4:36 pm

apochronaut wrote:
Thu May 26, 2022 1:11 am
Some companies kept infinity corrected condenser designs from the past but any of the modern Chinese ones I have looked at are finite. An infinity corrected condenser should be just as good as a finite condenser as long as , , ,
Thanks very much, I'll have an experiment :)
it has to be at least 30y old and probably a lot older ! So from your examples, makes it probable an infinity type.

Also, (from this and your notes to GerryR) I have now a better grasp on what I had been reading about Köhler, so far I have been using an led array with a thick translucent plastic block as a diffuser

Apologies to Louise for the temporary hijack of the topic :)

LouiseScot
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Re: LED Illumination Comparison

#29 Post by LouiseScot » Thu May 26, 2022 4:39 pm

SWmicro wrote:
Thu May 26, 2022 4:36 pm
apochronaut wrote:
Thu May 26, 2022 1:11 am
Some companies kept infinity corrected condenser designs from the past but any of the modern Chinese ones I have looked at are finite. An infinity corrected condenser should be just as good as a finite condenser as long as , , ,
Thanks very much, I'll have an experiment :)
it has to be at least 30y old and probably a lot older ! So from your examples, makes it probable an infinity type.

Also, (from this and your notes to GerryR) I have now a better grasp on what I had been reading about Köhler, so far I have been using an led array with a thick translucent plastic block as a diffuser

Apologies to Louise for the temporary hijack of the topic :)
No worries!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

SWmicro
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Re: LED Illumination Comparison

#30 Post by SWmicro » Sun May 29, 2022 8:18 pm

dtsh wrote:
Tue May 24, 2022 6:55 pm
LouiseScot wrote:
Tue May 24, 2022 6:28 pm
I think. If I was of a mind to I could dig out my slit spectrometer, get it up and running again, and point it at some LEDs... :)

Louise
I'd be interested in seeing that thread.
Me three ;)

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