90 % of the photographs on this website were taken with a very low-end camera, the Kodak Z740 :

Kodak Easy Share Z740

The problem I encountered was that the definition was not very good so I resampled each picture as follows through Photoshop .

You have the procedure well explained by clicking on this link : Adobe Help , it may help you too .

Resizing Picture Photoshop

Thanks to adobe for their illustration :)

My pictures were in low resolution so I doubled the size of each picture and for a better print , I changed the resolution of 72 pixels per inch to 300 ppp by checking " Resample Picture " on Photoshop . I tested an enlargement 40 x 60 cm as in the picture below and the result is more than satisfactory :

Essai tirage 40 x 60 cm

Zoom in :

Zoom Image

Meanwhile , I bought a new camera , the Nikon D850 :

Nikon D850

Since , no more problem about resolution , now I have more than 45 mega pixel :D

My lens is a Sigma 50 mm F1.4 DG HSM Art 

Sigma 50 00 F1.4

Calibration

Pictures were calibrated with Lightroom software .

Lightroom Classic CC

I also used Photoshop to resize some pictures for example .

Photoshop CC 2018

I work with a calibrated display : BenQ  SW2700PT

BenQ SW2700PT

My calibration probe i1 Display Pro de X-Rite

i1 Display Pro - X-Rite

It is important to work with a calibrated display .

In this regard , you may find color differences if you look at my pictures with a non-calibrated display such as laptops or other computers . Indeed , according to the manufacturers or the retailers , the commercial screens do not all have the same color temperature , the same luminance . Some may have a red , blue or green dominant while being far too bright .

My display has these values below :

 Luminance : 120 cd/m²

Color temperature : 6500 K